Rethink localization of strings used in LOGGER calls

[kelemeng]

Currently there is a lot of LOGGER calls in the code with inconsistent language: some strings are German, some are English.
Some are marked for translation with the L.m() call, some are not.
Proposal is:
(1) Translate all such strings to English
(2) Rethink whether all these are really worth translating into all languages. Are these visible anywhere else than in the wollmux.log file?
Add/remove L.m() calls as deemed fit.

[smehrbrodt]

Yes having English strings for all LOGGER calls should be enough.
I started work here, feel free to do the rest.

git grep LOGGER | grep "L\.m"