more various l10n updates (14) (#3245)

* l10n: adding a few more translatable strings

Minor adding of a strings within the subnet overview sites and split of
one existing string concatenation.

* l10n: making action menu translatable for customers view

* l10n: making action menu translatable for pstn view

* l10n: making action menu translatable for rackss view

* l10n: making action menu translatable for bgp view

* l10n: making action menu translatable for search results

* l10n: making action menu translatable for vaults view

* l10n: making action menu translatable for vlans view

* l10n: making action menu translatable for vrf view

* l10n: making outstanding action menus translatable

* footer.php: remove non working usage of l10n macro

With dd2aeb43 a option for showing a custom footer message was
introduced. The usage of the _() macro isn't and can't work that way.
And there is no need to use localization here, the user will use a
"customized" message, means he will use already use the preferred
language!
And even if the message is saved within the database, the user will also
here use his preferred language.

* l10n: Update German translations

Update the po file and also the binary message catalogue for German after
reworking various source files.

* l10n: Remove print_actions() indirect translations.

Don't double translate text field.

Co-authored-by: Gary Allan <github@gallan.co.uk>