- TODO: the server services plugin is not capable of enabling and disabling addon plugins, yet

Fixed #4443 Error in the template htm /usr/local/ispconfig/interface/web/client/templates/client_edit_limits.htm

- added limit for letsencrypt and directive snippets selector to client limits
- hide ssl tab if letsencrypt is selected

- removed most static content from scrigo

- cleaned up some javascript

- Included new icons and buttons
- Layout scaling improved (up to 1260px width)

- Added HHVM to "Default PHP Handler" field (server configuration).
- Fixed "Unable to load the server configuration from database." error when running server.sh.
- Fixed Javascript (accordions weren't working anymore, directive snippets and other placeholders couldn't be added anymore).

- Added section toggle for client limits

- Resellers can use templates for their clients.