Moved the section repeatable script into a separate class.
- Made the section repeater script to show section title when only one section remains after a remove event occurs.
- Made the section repeater script to hide section title when the first item(section) is repeated.
- Made the section repeater script to repeat section descriptions.
Changed the section repeater mechanism to hide the title and description rather tan making them empty so that the script can flexibly show them when necessary.
Revived the `section_head_{...}` hook by only applying to the description part (the section title will not be included anymore)
Applied the changes to the minified version.