Clean up BOTMETA.yml (#44574)

This PR includes:
- Removal of maintainers that are listed as author in the module
- Removal of entries that do not extend the original author list
- Move ignored-statement to namespace/directory (where useful)
- In some cases, fix the authors-list or add missing github id

We end up with a list of exceptions/additions and a large set of
namespace/directory maintainers or team of maintainers.

Some entries could be further improved by discussing with some
maintainers.

lib/ansible/modules/source_control/git_config.py

@@ -19,8 +19,8 @@ DOCUMENTATION = '''
 ---
 module: git_config
 author:
-  - "Matthew Gamble"
-  - "Marius Gedminas"
+  - Matthew Gamble (@djmattyg007)
+  - Marius Gedminas
 version_added: 2.1
 requirements: ['git']
 short_description: Read and write git configuration