Add support for importlib.resources (#78915)

* Add support for importlib.resources

* Remove the importlib.resources imports

* return the correct data

* Some code comments, and re-order for consistency

* Disallow traversing packages below an individual collection

* Add a traversable class for namespaces

* Re-use variable

* Utilize itertools.chain.from_iterable

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>

* Simplify logic to check for packages from ansible loaders

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>

* Just a generator expression, instead of a generator

* docstrings

* Add comment about find_spec for our namespaces

* Add some initial unit tests for importlib.resources

* normalize

* Utilize importlib.resources for listing collections

* collections_path is already in config, just use config

* install uses a different default for collections_path

* Remove unused import

* Remove duplicate __truediv__

* Bring back TraversableResources

* Apply some small suggestions from code review

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>
Co-authored-by: Matt Davis <6775756+nitzmahone@users.noreply.github.com>

* Remove cross contamination between plugin loader code and CLI code

* Remove unused import

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>
Co-authored-by: Matt Davis <6775756+nitzmahone@users.noreply.github.com>

requirements.txt

@@ -7,6 +7,9 @@ jinja2 >= 3.0.0
 PyYAML >= 5.1  # PyYAML 5.1 is required for Python 3.8+ support
 cryptography
 packaging
+# importlib.resources in stdlib for py3.9 is lacking native hooks for
+# importlib.resources.files
+importlib_resources >= 5.0, < 5.1; python_version < '3.10'
 # NOTE: resolvelib 0.x version bumps should be considered major/breaking
 # NOTE: and we should update the upper cap with care, at least until 1.0
 # NOTE: Ref: https://github.com/sarugaku/resolvelib/issues/69