When running `ansible-doc --list` a lot of errors are
generated when `ansible-doc` tries to find documentation
strings in `.pyc` files.

Fixes #9316

Fixes #9399

This reverts commit a6029264.

Fixes #9400

Update intro_installation.rst

Add host to polling message

* moved old unittests for vault over to the new codebase
* reverted YAML error helpers and reverted the load() function
  in parsing/__init__.py, pending a rewrite of a new YAML loader
  class of some kind to encapsulate all of that
* fixed an error in in the module args parser regarding the shell/
  command argument parsing, where some additional arguments were
  being lost

Corrected casing of Jinja2 in pip dependencies.

Debian/Ubuntu doesn't have group nobody so remove the group portion of the new template tests as owner and mode will exercise the problematic code path

integration tests

Fixes #9350

Change "usuable" to "usable".

Fix typo

`Propspective` -> `Prospective`

The message for when an async task has finished has the hostname in it. This adds it to the polling message as well:

```
<job 390794962174.18311> finished on 107.6.24.140
<job 390794962174.31779> finished on 69.90.50.171
<job 390794962174.12328> polling on 69.90.50.172, 6840s remaining
```

Added _meta hostvars key to gce.py plugin

Fixes #9333

* using inspect module instead of iteritems(self.__class__.__dict__, due
  to the fact that the later does not include attributes from parent
  classes
* added tags/when attributes to Base() class for use by all subclasses
* removed value/callable code from Attribute, as they are not used
* started moving some limited code from utils to new places in v2 tree
  (vault, yaml-parsing related defs)
* re-added ability of Block.load() to create implicit blocks from tasks
* started overhaul of Role class and role-related code

Detect docker as virtualization_type

Detect kvm guests through sys_vendor.