Refactor EditTitleMacro (wiki macro) as a velocity macro

Currently the EditTitleMacro is defined as a Wiki Macro, but its functionality is a velocity macro.
Because is defined as a Wiki Macro, it appears in the WYSIWYG - "Insert Macro" dialog, but this macro is not supposed to be used by normal users.

We should:

• refactor it as a velocity macro in ForumCode.Macros;
• look for the places where this macro is called and replace the calls
• remove the EditTitleMacro page