[Code Style] Changes in tag standards: Frontend Comments

This pull should fix the issue detailed here: joomla/coding-standards#80

I have broken in parts this original pull #4590 to make it easy for review. This pull is contains only the Frontend Comments.
The rest of the changes are going to be sent in different pulls.

This pull is related to #4603, #4625, #4632, #4636 and #4617.