Add "Reset Template Cache" button to "Tools -> Service" section

I would be great to have button, that will delete all compiled versions of templates, that are currently stored under "/system/cache" folder. Depending on how web server is configured it's not always possible to delete these files by hand over FTP or SSH connection.

I propose to call "/system/cache/clean.sh" script or just recursively delete all files like "clean.sh" script does.