added German ra translation including small fixes

- don't translate dropdown chrome yaml (no text)
- remove spurious external port text (should be numerical)
- use msloicon2 workaround only for English translation
- use aftermath/counter-strike mix files to avoid conflicts
- remove tooltip from fake radar dome as it might reveal it
- fix missing allies/soviet name string in fr/en
- use textless icons only when l10n does not provide them
Merge branch 'localisation' of https://github.com/Mailaender/OpenRA into localisation