Using set_host_overrides() in the connection plugin to access the ssh
argument variables from the inventory didn't see group_vars/host_vars
settings, as noted earlier. Instead, we can set the correct values in
the PlayContext, which has access to all command-line options, task
settings, and variables.

The only downside of doing so is that the source of the settings is no
longer available in ssh.py, and therefore can't be logged. But the code
is simpler, and it actually works.

This change was suggested by @jimi-c in response to the FIXME in the
earlier commit.

Now we have the following ways to set additional arguments:

1. [ssh_connection]ssh_args in ansible.cfg: global setting, prepended to
   every command line for ssh/scp/sftp. Overrides default ControlPersist
   settings.
2. ansible_ssh_common_args inventory variable. Appended to every command
   line for ssh/scp/sftp. Used in addition to ssh_args, if set above, or
   the default settings.
3. ansible_{sftp,scp,ssh}_extra_args inventory variables. Appended to
   every command line for the relevant binary only. Used in addition to
   #1 and #2, if set above, or the default settings.
3. Using the --ssh-common-args or --{sftp,scp,ssh}-extra-args command
   line options (which are overriden by #2 and #3 above).

This preserves backwards compatibility (for ssh_args in ansible.cfg),
but also permits global settings (e.g. ProxyCommand via _common_args) or
ssh-specific options (e.g. -R via ssh_extra_args).

Fixes #12576

should be last commit that fixes #12214

normalized outputs to use display class
cleaned up unused imports

Fixes #12582

Alphabitize retry_files_enabled and retry_files_save_path

Document vars

merging so we can push PRs against the common repo

Remove mysterious old cruft

The two lines were added in 2673eb0a and modified in 60e1a1f8, but foo
is completely unused. Removing it doesn't break anything: out it goes!

Update consul integration test with http checks

Remove an unwanted FIXME annotation
ok, confirmed we don't want to support it 

Fixes #12590

<crab> jimi|ansible: do you think it should be possible to add both
       foo:22 and foo:23 to the inventory?
<jimi|ansible> no

…so we don't want an invitation to FIXME.

Windows: Updated docs

Python 3: fix most tests for ansible.module_utils.basic

Put retry_files_enabled and retry_files_save_path into alphabetical order. Found when investigating #11491