New application role : CacheReset

• ​What? Defines which roles are able to clear the cache by typing "cache" in the URL.
• Why? Because not everyone may be able to reset the shared cache of the application.
• How? Settings -> User, Organisations and privileges -> Roles -> Choose role -> Application Areas -> CacheReset: Check the execute checkbox if this role needs to be able to reset cache. All accountholders are by default able to reset cache