Made ansible-doc more plugin agnostic
We can have docs in lookup, callback, connectionm strategy, etc
Use first docstring and make pepizis happy
generalized module_docs to plugin_docs
documented cartesian, ssh, default, jsonfile, etc as examples
changed lack of docs to warning when listing
made smarter about bad docstrings
better blacklisting
added handling of options/config/envs/etc
move blacklist to find_plugins, only need once
Fixes bugs related to creating Templar() objects on the fly, where
the shared loader objects (serialized to TaskExecutor) aren't used
so information loaded into plugin loaders after forking is lost.
Fixes#11815