Resolve "Feature: Account Menu in Top Navbar"

Closes #531

See merge request !907

# Conflicts:
#   CHANGELOG.rst

Resolve "Improve mobile design of login page"

Closes #572

See merge request !905

# Conflicts:
#   CHANGELOG.rst

Add retry button to 500 page

See merge request !972

Release 2.7.4

See merge request !969

Translations update from Weblate

See merge request !947

Currently translated at 100.0% (651 of 651 strings)

Translation: AlekSIS/AlekSIS-Core
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-core/de/

Update trans files

See merge request !968

Resolve "Allow more than one person without e-mail address to be invited"

Closes #652

See merge request !967

Merge branch '651-show-invitation-code-when-existing-person-without-email-is-invited-otherwise-show-that-email' into 'master'

Resolve "Show invitation code when existing person without email is invited, otherwise show that email was send"

Closes #651

See merge request !966

Resolve "Add invited person to invitation table"

Closes #650

See merge request !965

Fix invite permissions

See merge request !955

Disable check for existing person invitation with same e-mail address if person has no e-mail address

More cachalot fixes

See merge request !964

Invalidate both database backends

See merge request !963

Resolve "Fix success redirect url of signup view"

Closes #647

See merge request !962

Resolve "extends must be the first tag in the template. [Ticket#751089]"

Closes #645

See merge request !960

Merge remote-tracking branch 'origin/master' into 645-extends-must-be-the-first-tag-in-the-template-ticket-751089

Do not clear cache in migration container die to session invalidation issues

See merge request AlekSIS/official/AlekSIS-Core!961