Integrate Ansible core tower modules content into AWX

This commit includes all the changes involved in
converting the old Ansible Tower modules from commits
in Ansible core into the AWX collection that replaces it.
Also includes work needed to integrate it into the
AWX processes like tests, docs, and the Makefile.

Apply changes from content_collector tool

Add integrated module tests
  operate via run_module fixture
  add makefile target for them

Add flake8 target and fix flake8 errors

Update README

Make consolidated target for testing modules

awx_modules/README.md

@@ -0,0 +1,52 @@
+# AWX Ansible Modules
+
+These modules allow for easy interaction with an AWX or Ansible Tower server
+in Ansible playbooks.
+
+The previous home for these modules was in https://github.com/ansible/ansible
+inside the folder `lib/ansible/modules/web_infrastructure/ansible_tower`.
+
+## Running
+
+To use these modules, the "old" tower-cli needs to be installed
+in the virtual environment where the modules run.
+You can install it from either:
+
+ - https://github.com/ansible/tower-cli/
+ - https://pypi.org/project/ansible-tower-cli/
+
+To use these modules in AWX, you should create a custom virtual environment
+to install the requirement into. NOTE: you will also probably still need
+to set the job template extra_vars to include `ansible_python_interpreter`
+to be the python in that virtual environment.
+
+## Running Tests
+
+Tests to verify compatibility with the most recent AWX code exist
+in `awx_modules/test/awx`. These tests require that python packages
+are available for all of `awx`, `ansible`, `tower_cli`, and the modules
+themselves.
+
+The target `make prepare_modules_venv` will prepare some requirements
+in the `awx_modules_test_venv` folder so that `make test_modules` can
+be ran to actually run the tests. A single test can be ran via:
+
+```
+make test_modules MODULE_TEST_DIRS=awx_modules/test/awx/test_organization.py
+```
+
+## Building
+
+To build, you should not be in the AWX virtual environment.
+This should work on any machine that has a sufficiently recent version
+of Ansible installed.
+
+```
+cd awx_modules
+ansible-galaxy build
+```
+
+This will leave a tar file in the awx_modules directory.
+
+This process may be amended in the future to template components of `galaxy.yml`
+from values (such as version) taken from AWX.