[BUG] Several files are using utf-8 encoding, should use ACSII

[peterzhuamazon]

Describe the bug
opensearch-project/opensearch-build#635 (comment)

These files cause build failure due to encoding not in ASCII:

src/main/java/org/opensearch/ad/caching/CacheBuffer.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/caching/PriorityCache.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/caching/PriorityTracker.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/model/Entity.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/ratelimit/ColdEntityWorker.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/ratelimit/RateLimitedRequestWorker.java: UTF-8 Unicode text
src/main/java/org/opensearch/ad/model/ADTaskState.java: Java source, UTF-8 Unicode text
src/main/java/org/opensearch/ad/model/InitProgressProfile.java: Java source, UTF-8 Unicode text

/tmp/tmpbcap9s69/anomaly-detection/src/main/java/org/opensearch/ad/caching/CacheBuffer.java:54: error: unmappable character (0x80) for encoding US-ASCII
 * We use a layered cache to manage active entities??? states.  We have a two-level
                                                    ^
/tmp/tmpbcap9s69/anomaly-detection/src/main/java/org/opensearch/ad/caching/CacheBuffer.java:54: error: unmappable character (0x99) for encoding US-ASCII
 * We use a layered cache to manage active entities??? states.  We have a two-level
                                                     ^
/tmp/tmpbcap9s69/anomaly-detection/src/main/java/org/opensearch/ad/caching/CacheBuffer.java:56: error: unmappable character (0xE2) for encoding US-ASCII
 * dedicated cache that stores ten (dynamically adjustable) entities??? states per
 * ```

**Other plugins installed**
Please mention if you are using this plugin along side any other plugin. Security for example.

**To Reproduce**
Run the build on Jenkins with `./gradlew assemble --no-daemon --refresh-dependencies -DskipTests=true -Dopensearch.version=1.1.0 -Dbuild.snapshot=false` on CentOS7.
Not producible on local only on Jenkins.

**Expected behavior**
Javadoc build correctly without this unmapping issues.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Desktop (please complete the following information):**
 - OS: [e.g. iOS]
 - Browser [e.g. chrome, safari]
 - Version [e.g. 22]

**Additional context**
Add any other context about the problem here.

[peterzhuamazon]

#245
#246
#247

[peterzhuamazon]

As a fix later we can try https://gist.github.com/rponte/d660919434d094bbd35a1aabf7ef1bf0 to enable utf-8 encoding.

[peterzhuamazon]

Adding these to fully resolve the issues:

tasks.withType(JavaCompile) {
        options.encoding = "UTF-8"
}
tasks.withType(Test) {
        systemProperty "file.encoding", "UTF-8"
}
tasks.withType(Javadoc) {
    options.encoding = 'UTF-8'
}

Logs:

2021-09-29 20:55:54 INFO     Building anomaly-detection
2021-09-29 20:55:54 INFO     Executing "git init" in /tmp/tmpcfupmjmj/anomaly-detection
2021-09-29 20:55:54 INFO     Executing "git remote add origin https://github.com/opensearch-project/anomaly-detection.git" in /tmp/tmpcfupmjmj/anomaly-detection
2021-09-29 20:55:54 INFO     Executing "git fetch --depth 1 origin opensearch-ascii-utf8" in /tmp/tmpcfupmjmj/anomaly-detection

2021-09-29 20:55:55 INFO     Executing "git checkout FETCH_HEAD" in /tmp/tmpcfupmjmj/anomaly-detection
2021-09-29 20:55:55 INFO     Executing "git rev-parse HEAD" in /tmp/tmpcfupmjmj/anomaly-detection
2021-09-29 20:55:55 INFO     Checked out https://github.com/opensearch-project/anomaly-detection.git@opensearch-ascii-utf8 into /tmp/tmpcfupmjmj/anomaly-detection at f780eed22a044c29a0906c8da44c9f25316779e6
2021-09-29 20:55:55 INFO     Executing "/var/jenkins/workspace/bundle_pipelines/bundle-build_1.0.1@4/bundle-workflow/scripts/default/opensearch/build.sh -v 1.1.0 -a x64 -s false -o artifacts" in /tmp/tmpcfupmjmj/anomaly-detection
+ getopts :h:v:s:o:a: arg
+ case $arg in
+ VERSION=1.1.0
+ getopts :h:v:s:o:a: arg
+ case $arg in
+ ARCHITECTURE=x64
+ getopts :h:v:s:o:a: arg
+ case $arg in
+ SNAPSHOT=false
+ getopts :h:v:s:o:a: arg
+ case $arg in
+ OUTPUT=artifacts
+ getopts :h:v:s:o:a: arg
+ '[' -z 1.1.0 ']'
+ [[ false == \t\r\u\e ]]
+ '[' -z artifacts ']'
+ mkdir -p artifacts
+ ./gradlew assemble --no-daemon --refresh-dependencies -DskipTests=true -Dopensearch.version=1.1.0 -Dbuild.snapshot=false

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedClass (file:/usr/share/opensearch/.gradle/wrapper/dists/gradle-6.6.1-all/ejrtlte9hlw8v6ii20a9584rs/gradle-6.6.1/lib/groovy-all-1.3-2.5.12.jar) to method java.lang.Object.finalize()
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.CachedClass
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

=======================================
OpenSearch Build Hamster says Hello!
  Gradle Version        : 6.6.1
  OS Info               : Linux 4.14.243-185.433.amzn2.x86_64 (amd64)
  JDK Version           : 14 (AdoptOpenJDK)
  JAVA_HOME             : /usr/lib/jvm/adoptopenjdk-14-hotspot
  Random Testing Seed   : A8C414858B0C50D1
  In FIPS 140 mode      : false
=======================================

> Task :compileJava
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

> Task :processResources
> Task :classes
> Task :jar
> Task :copyPluginPropertiesTemplate
> Task :pluginProperties
> Task :bundlePlugin
> Task :generatePomFileForNebulaPublication
> Task :generatePom

> Task :javadoc
> Task :javadocJar
> Task :sourcesJar
> Task :assemble

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 52s

[peterzhuamazon]

#249
#250
#251