Changed German wording for value `unchecked` for both public_trial and archival_value:

"Noch nicht geprüft" -> "Nicht geprüft"

(cherry picked from commit e2ea11a19ee63201521cf65ef527ea34cf2b23f8)
Harmonize translation defaults, to avoid i18ndude warnings.

(cherry picked from commit f6a7f140fbddbce635d25922c2177658f8d2de78)
Fixed translation for filing_number column in dossier listings.

(cherry picked from commit a7e6430b858ae77fc5845680054866dc87e3c54a)
Also check for not supplied mails, when check if dossier could be resolved.

(cherry picked from commit 0cf827a780e5c34a8b64fa7627f7987803682c2d)
Don't encode attached mails when sending documents as email.

(cherry picked from commit a8ee3ec5cacddeed554a205a94c31c01356e27f4)
Change german wording for descriptions of `public_trial` and `public_trial_statement`

(cherry picked from commit 6aa8652113885f89d9d88c2c82dc66cec3e9715f)
Upgrade-Step: Create initial journal entry for mails.

(cherry picked from commit cb3ee1044855cc4b6c44af437d6f4fee843bf42f)
Always set `digitally_available` to `True` upon mail creation.

(cherry picked from commit 6ffe5dca5d2f9cfcd2fafc78fe10aae742dccef3)
Merge pull request #499 from 4teamwork/lg-backport-dev-feedback-changes

Backport changes based on feedback from DEV system