fix(ingest/gc): add limit, add actual loop for iterating over batches

[anshbansal]

• there was no actual loop iterating over batches, added that
• references were not being deleted, added that
• added a limit of number of entities to be deleted so a single run doesn't go endlessly for ever risking multiple runs starting concurrently

Checklist

• [ ] The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• [ ] Links to related issues (if applicable)
• [ ] Tests for the changes have been added/updated (if applicable)
• [ ] Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• [ ] For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub

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