Fixes #2341, fixes #2317: moved codeception dependecies to "suggest" section, fixed codeception version on stable branch

This reverts commit 7145b9e9.

Revert "Fixes #1856: The default CSS class for hint generated by `ActiveField` is changed to `help-block`"

This reverts commit 7ae4695d.

fixes #1913

no need to download codeception via composer when phar is used.
fixes #1913

Removed error-block HTML class and related styles and used Bootstrap3 standard practice about errors instead

1. It results in much smaller download and takes less disk space (25MB instead of 180MB for yii-basic + dependencies).
2. It requires less utilities to be installed (no VCS binaries required).
3. It takes less time to install dependencies.

to allow specific styling
also fixed an issue with gridview sort indicator css.

fixes #1000