Add requirements files for python dependencies

This commit adds two separate requirements files that you can feed into
pip for installing python dependencies.

This makes it easier for contributors to install dependencies by having
them isolated to a couple specific files, instead of having to reference
build documentation.

docs/manual/developer/02_building_complianceascode.md

@@ -53,6 +53,24 @@ apt-get install cmake make libopenscap8 libxml2-utils ninja-build python3-jinja2
 
 IMPORTANT: Version `1.0.8` or later of `openscap-utils` is required to build the content.
 
+### Python Dependencies
+
+Some python dependencies must be installed through pip because they're not
+packaged by a distribution.
+
+Dependencies for developing are in `requirements.txt` and you can install them using:
+
+```bash
+$ pip3 install -r requirements.txt
+```
+
+Test dependencies are kept in a separate requirements file called
+`test-requirements.txt` and are installed using the same process:
+
+```bash
+$ pip3 install -r test-requirements.txt
+```
+
 ### Git (Clone the Repository)
 
 Install git if you want to clone the GitHub repository to get the
@@ -92,11 +110,9 @@ apt-get install bats
 
 ### xmldiff (Python unit tests)
 
-Install the  `xmldiff` and `lxml` packages to execute Python unit tests that use these packages.
+Install the `lxml` package to execute Python unit tests that use these packages.
 
 ```bash
-pip3 install xmldiff
-
 # Fedora/RHEL
 yum install python3-lxml
 
@@ -120,11 +136,9 @@ apt-get install yamllint ansible-lint
 
 ### Static Ansible Playbooks tests
 
-Install `yamlpath` and `pytest` to run tests cases that analyse the Ansible
+Install `pytest` to run tests cases that analyse the Ansible
 Playbooks' yaml nodes.
 ```bash
-pip3 install yamlpath
-
 # Fedora/RHEL
 yum install python3-pytest
 
@@ -145,14 +159,6 @@ yum install ninja-build
 apt-get install ninja-build
 ```
 
-### json2html (HTML Report Statistics)
-
-Install the `json2html` package if you want to generate HTML report statistics:
-
-```bash
-pip install json2html
-```
-
 ### Sphinx packages (Developer Documentation)
 
 Install Sphinx packages if you want to generate HTML Documentation, from source directory run:
@@ -211,17 +217,6 @@ yum install python3-mypy
 apt-get install python3-mypy
 ```
 
-#### Type stubs
-
-```bash
-pip install types-openpyxl types-PyYAML openpyxl-stubs
-```
-
-### cmakelint (Linting CMake Files)
-```bash
-pip install cmakelint
-```
-
 ## Downloading the source code
 
 Download and extract a tarball from the [list of releases](https://github.com/ComplianceAsCode/content/releases):

requirements.txt

@@ -0,0 +1,5 @@
+cmakelint
+types-openpyxl
+types-PyYAML
+openpyxl-stubs
+json2html

test-requirements.txt

@@ -0,0 +1,2 @@
+yamlpath
+xmldiff