Adding Integration Tests for mysql_db module

Adding the following Test Coverage for RedHat and Debian OS:

 - Use mysql_db module to create, delete databases using different encoding.
 - Backup/Restore databases using different file format: sql, gz and bz2.
 - Create and delete databases using different user privilege.
 - Assert database creation, deleting and content using system commands.
fix for unarchive 8257
Merge pull request #8263 from bennojoy/unarchive_fix

fix for unarchive 8257
Add a lot of tests to verify parsing routines for scenarios that should pass.  Some changes TBD, like stripping command spaces off end of expressions.
Add some negative tests on the same parsing infrastructure.
Add missing role test file.
Add missing file.
Fixes to parsing tests to remove trailing space
Fixes for module param counting and additional shell quoting issues
Make sure 'item' variable is set when using first_available_file

Fixes #8220
Merge branch 'integration_mysql_db' of https://github.com/wrosario/ansible into wrosario-integration_mysql_db
Merge branch 'wrosario-integration_mysql_db' into devel
Make code more PEP8 compliant (if(x))

Remove useless parentheses, `if (x):` should be `if x:`.
Make code more PEP8 compliant (whitespace)

> Always surround these binary operators with a single space on either
> side: assignment (`=`), augmented assignment (`+=`, `-=`
> etc.), comparisons (`==`, `<`, `>`, ``!=``, `<>`, `<=`,
> `>=`, `in`, `not in`, `is`, `is not`), Booleans (`and`,
> `or`, `not`).
Make docker inventory plugin more Pythonic

There's no need to check if kwargs is empty before iterating over it.
Refactor CronTab.is_empty
Make code more PEP8 compliant (if len(seq))

> For sequences, (strings, lists, tuples), use the fact that empty
> sequences are false.
>
>     Yes: if not seq:
>          if seq:
>
>     No: if len(seq)
>         if not len(seq)