Replace Slack reporting by Sentry reporting

See merge request !875

Use python3 venv module instead of pyvenv

See merge request !874

Access Sentry access permission and API call to provide necessary auth info

See merge request !866

Remove trailing whitespaces

See merge request !873

Fix punctuation discrepancies in the translations

See merge request !871

Fix/registrations form entry missing

Closes #664

See merge request !868

Resolve "Fix names of categories of pushnotifications"

Closes #663

See merge request !860

Fix typo in push notification devices viewset

See merge request !862

Fix some small bugs in translations

See merge request !861

Resolve "Automatic generation of board email addresses"

Closes #649

See merge request !844

No linenos in po

See merge request !859

Fix registration options to not be required

See merge request !858

The translation files are fully changing all the way and that leads to
diffs not being inspected. This overrides the defaults of the
`makemessages` command in an ugly way, but it works.

Fix sorting of registration dates in event admin

Closes #653

See merge request !854

Add optins to members registration form

Closes #658

See merge request !849

Fix member expiration emails

See merge request !856

Add LectureYear filter to EventAdmin

Closes #403

See merge request !853

Add privacy policy checkbox to renewal form

Closes #657

See merge request !855

Get CELERY_BROKER_URL from env vars as a whole

See merge request !852

Do not schedule or delete messages for unpublished events

Closes #655 and #656

See merge request !847