Prepare for 1.27.4 minor release

1. General notes: upgrade to Ubuntu 22.04 as base supported OS: !838 (merged)
2. New features:
   • new virtual operations emitted: !332 (merged)
   • prepare code for new Hardfork 28
   • prerequisites for strict matching of Hived data structures to the shared_memory.bin and snapshot contents: !784 (merged)
3. Hived bugfixes:
   • fixed shutdown problems:
     • while executing broadcast_transaction_synchronuous: !812 (merged)
     • when --exit-before-sync was used: !833 (merged)
   • plugin/index state is more strict verified (Issue #423 (closed)): !772 (merged)
   • fixed cli_wallet shutdown problems leading to random failure: !726 (merged)
   • elimination of custom fc::uint128 implementation (standard builtin GCC type is used): !804 (merged)
   • silent truncation of fixed_string is eliminated (what could lead to silent modification of broken operations in transaction - now they will explicitly fail): !794 (merged)
   • Fixed transaction counter in AH RockDB plugin (to improve reporting): !850 (merged)
   • Fixed impacted account collection (leads to AH collection) for comment_payout_beneficiaries: !844 (merged)
   • Account History API better handles history data coming from reversible blocks: !866 (merged)
   • RC mana can't go under zero anymore: !863 (merged)
4. Python regression test improvements:
   • !811 (merged)
   • !683 (merged)
   • !813 (merged)
   • database_api suite extended: !516 (merged)
   • dedicated performance test suite for recurrent transfers to show corner cases: !823 (merged)
   • enhanced suite related to condenser_api, transaction_status_api !816 (merged), !795 (merged)
   • created tests specific to decline_voting_rights and proxy operations: !851 (merged), !815 (merged)
   • new tests for market_history_api: !826 (merged)
   • enhanced tests specific to recurrent transfers: !807 (merged)
5. Low level unit tests extended by suite of tests covering AH calls (prerequisites to internal code cleanup/refactoring, which will need good test base):
   • !810 (merged)
   • !825 (merged)
   • !862 (merged)
   • !867 (merged)
   • !874 (merged)
6. Devops/workflow automation:
   • dockerized setup fixes/simplifications (mostly solved permission issues):
     • !865 (merged)
     • !869 (merged)
   • Simplify replay of test node and use GitLab cache to lower resource usage during testing: !801 (merged)
   • Official Hive images can be published by automatic job: !868 (merged)