GitLab

Add new dark mode

Closes #618, #602, #603, #611, #573, #34, #30, #35, #32, #31, #29, #609, #12, #11, #10, #14, #5, #4, #1, and #2

See merge request arsnova/cards!1177

Resolve "error reporting modal button which links to the GitLab issue list"

Closes #602

See merge request arsnova/cards!1153

Merge branch '573-allow-cardset-owners-to-see-histories-from-previous-bonus-sessions' into 'staging'

Resolve: 573-allow-cardset-owners-to-see-histories-from-previous-bonus-sessions

Closes #603, #611, and #573

See merge request arsnova/cards!1163