Merge branch 'admin-api-change-password' into 'develop'

Admin API: `PATCH /api/pleroma/admin/users/:nickname/update_credentials`

See merge request pleroma/pleroma!2149

diff --cc CHANGELOG.md
Simple merge

diff --cc lib/pleroma/user.ex
Simple merge

diff --cc lib/pleroma/web/mastodon_api/controllers/account_controller.ex
Simple merge

diff --cc lib/pleroma/web/router.ex
Simple merge

diff --cc test/web/admin_api/admin_api_controller_test.exs
Simple merge