Implement service level interceptors using InterceptableService

[dilanSachi]

Description:
For the details discussion, refer the original discussion [1].

• Add InterceptableService to http module and get the service level interceptors using this initInterceptors() function.
• Give a warning/compiler error when interceptors are added from both this function and the annotation
• Deprecate the usage of having the interceptors in the annotation (might be provided by the compiler plugin)
• Update the website and other samples

[1] #4300

[dilanSachi]

Give a warning/compiler error when interceptors are added from both this function and the annotation,

For this better to give a compile error rather than a warning right? As we cannot decide on a order of the interceptors in the runtime.
@TharmiganK

[dilanSachi]

Closing as this is completed