[ticket/12658] Add test for base case of command config:set

PHPBB3-12658
[ticket/12658] Add test for command config:set-atomic

PHPBB3-12658
[ticket/12658] Add test for command config:get

PHPBB3-12658
[ticket/12658] Add test for command config:increment

PHPBB3-12658
[ticket/12658] Add test for command config:delete

PHPBB3-12658
[ticket/12658] Fix typo and coding style mistakes

PHPBB3-12658
[ticket/12658] Refactoring code

PHPBB3-12658
[ticket/12658] Fix wrong eol character

PHPBB3-12658
[ticket/12658] Rebased and fixed unit tests

PHPBB3-12658
Merge pull request #2551 from ptitlazy/ticket/12658

[ticket/12658] Add test for base case of commands config:

* ptitlazy/ticket/12658:
  [ticket/12658] Rebased and fixed unit tests
  [ticket/12658] Fix wrong eol character
  [ticket/12658] Refactoring code
  [ticket/12658] Fix typo and coding style mistakes
  [ticket/12658] Add test for command config:delete
  [ticket/12658] Add test for command config:increment
  [ticket/12658] Add test for command config:get
  [ticket/12658] Add test for command config:set-atomic
  [ticket/12658] Add test for base case of command config:set