restore notifications page, fix z-index issues

Closes #1166

See merge request pleroma/pleroma-fe!1534

Layout refactoring + Three column mode

See merge request pleroma/pleroma-fe!1503

Fix Open Chat button

See merge request pleroma/pleroma-fe!1532

Fix registration error

See merge request pleroma/pleroma-fe!1527

Revert "Merge branch 'revert-a88abc7e' into 'develop'"

See merge request pleroma/pleroma-fe!1528

This reverts merge request !1526

Revert "Merge branch 'from/develop/tusooa/lang-opts' into 'develop'"

See merge request !1526

This reverts merge request !1494

Add language options

See merge request !1494

Update dependency semver to v5.7.1

See merge request !1491

Update dependency webpack-merge to v0.20.0

See merge request !1496

Update dependency @vuelidate/core to v2.0.0-alpha.41

See merge request !1501

Pass file name of cropped avatar to form data

See merge request !1522

Poll-end notifications

See merge request !1524

Ref: poll-notif

Ref: poll-notif

Ref: poll-notif

Ref: poll-notif

* origin/develop:
  Fix virtual scrolling when the user has a lot of pinned statuses
  fix "allow discovery" setting misbehaving

Fix virtual scrolling when the user has a lot of pinned statuses

See merge request !1523