services.cgi: Fix status/actions on services with name != addon name

services.cgi: Fix status/actions on services with name != addon name

* addonctrl's new functionality to control explicit addon services was
  implemented.
* Change 'Addon' column header to 'Addon Service' to be clear that
  it's not addons but services listed here.
* Services not matching the name of the addon now display the addon
  name between parentheses, so the user knows where the service comes
  from.
* When no valid runlevel symlink is found by addonctrl for a service,
  the 'enable on boot' checkbox is replaced by a small exclamation point
  with alt-text "No valid runlevel symlink was found for the initscript of
  this service." to inform user why a service can't be enabled.
* Added German and Dutch translation for above message.

Fixes: Bug#12935
Signed-off-by: Robin Roevens <robin.roevens@disroot.org>
Reviewed-by: Michael Tremer <michael.tremer@ipfire.org>