pre-release22

• Merge pull request #1550 from ITISFoundation/FREEZE_ChrigelMaurer_v2
• Merge branch 'staging' into FREEZE_ChrigelMaurer_v2
• allow forwarded headers from external reverse-proxy (#1548)
• Bump pytest-mock from 3.1.0 to 3.1.1 in /packages/service-library (#1545)
• Bump ujson from 2.0.3 to 3.0.0 in /packages/service-library (#1544)
• Fix director service discovery (#1538)
• [Maintenance] upgrades pytest 5.4.2 -> 5.4.3 (#1543)
• [bugfix] fixes projects_api and sets larger pool to webserver (#1539)
• Bump docker from 4.2.0 to 4.2.1 in /packages/postgres-database (#1541)