Fix order of resolving dependent role variables from vars files

Also adds a new class to the test_var_precedence test to check for
this type of error in the future.

Fixes #9178
This is an exceedingly rough sketch of what attributes might look like - metaclass implementations NOT complete.
Add attribute starter notes
WIP on refactoring changes
Update submodule reference
WIP on Attributes.  Getting closer.
atfork import warning should be suppressed when system_warnings = False

Fixes #9247
__getattr__ to hide some of the attribute magic.
Update base.py

updated with some notes
Documentation typo: ansible-module[s]-extras

Typo: ansible-module-extras -> ansible-modules-extras in a link to this
repository.
Fix bug in plugin path caching

Fixes #9263
Small fix for issue #9275
Template play vars after reading them

Fixes #9242
Revert "atfork import warning should be suppressed when system_warnings = False"

This reverts commit a175168686abedaad88051aedc2dab3d164ba792.
WIP on data structure processing patterns.
Add submodule references since v2 development will need them, the tree obviously does
not need two copies.
Work in progress on task loading.
Attribute defaults and optional accessors.
Attempt to clean up the munging functions a little.
Move over some of the parsing functions that we need.