Compacting: integrate into Flows system

[zaychenko-sergei]

User requirements:

• it should be possible to launch hard compacting manually for root datasets only
• it should be possible to override default settings for max slice byte size / number of records in UI
• we should not allow define a schedule for this type of the flow, as it's a dangerous operation
• derived datasets that are dependent on the compacted dataset will fail their next update, and that's expected
• failing transform flows of derived datasets should show a minimal error message explaining what happened

Technical requirements:

• rename existing compacting to HardCompacting, as we will have SoftCompacting at some future point
• update GraphQL schema to be able to launch compacting flow:
  • allow compacting-specific flow configuration options (max_slice_size, max_slice_records)
  • for manual triggers probably nothing extra should be done
  • for defining schedules, ensure a correct error is returned when attempted (not allowed for this type of flow)
  • add unit tests
• connect flow system and compacting service to execute HardCompacting flow
• compacting service should be configured using options defined in flow configuration, or with defaults, if no config is active
• propagate compacting result status to flows system up to GraphQL API:
  • extend flow summary/description/... for UI so that enough information is transformed
  • for compacting we are interested how many blocks we had initially, how many we have finally, and probably total number of records
  • add view API unit tests
• succesful completion of root compacting should initiate "ExecuteTransform" flows of derived datasets:
  • those datasets would fail for now
  • we need to ensure error message is shown up to API level
  • in near future, there will be another type of transforming, which resets previous results and re-calculates derived dataset from scratch, but we are skipping this for now
• cover flow system logic with solid integration tests ("time diagram" type of tests that is used for other flow system functions now)