runtime-1500 release

[github-actions]

• Merge fix author-slot-filter migration in nimbus #1439
• Merge [MOON-1453] calculate outgoing rewards based on pending revoke and decrease changes #1408
• Merge v0.9.19 Dependency Update #1438
• Create a PR that increment spec version (like upgrade runtime to 1001 #1051)
• Cleanup previous migrations (only for major release,
  https://github.com/PureStake/moonbeam/blob/master/runtime/common/src/migrations.rs)
• Get that PR approved and merged
• Tag master with runtime-1500 and push to github
• Start the github action Publish Runtime Draft
  with runtime-1401 => runtime-1500
• Review the generated Draft and clean a bit the messages if needed (keep it draft)
• Create the tracing runtime on moonbeam-runtime-overrides
  (see https://github.com/PureStake/moonbeam-runtime-overrides/blob/master/README.md)
• Add new substitute in stagenet configuration
• Upgrade stagenet
• Add new substitute in alphanet configuration
• Upgrade alphanet
• Create new tracing image for partners: start the github action Publish Docker
  with v0.22.1 and master
• When everything is ok, publish the draft release

[crystalin]

Replaced by #1452