[Audit remediation] Suggestion 1: Adopt a Verifiable Database / Batch Format

[begmaroman]

• Added migration for adding batch_num column to offchain_data table.
  • The migration resets the last block number for L1 task in order to trigger resync process that will updated batch number in all existing records.
• Updated DB layer logic to handle a new field.
• Updated handleUnresolvedBatches function to populate a batch number field
  • It also populates a batch number field for existing records. This is needed to updated batch number in all existing records.

[sonarcloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
89.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[Stefan-Ethernal]

Generally LGTM, though it is strange to me this part around having SyncTask as a type alias and providing it as a parameter, since it is always the L1SyncTask value.