feat: More purge_ttl features

[AzureMarker]

Description

• Add --mode/PURGE_MODE to choose if batches, bsos, or both tables should be purged.
• Add --expiry_mode/PURGE_EXPIRY_MODE to choose if the expiry should be compared against midnight or now.
• Support serially deleting UID prefixes by regex, with --uid_prefixes/PURGE_UID_PREFIXES.
  • This is a list of regex, ex. [^[a-h],^[i-p]].
  • Each entry is a separate purge run.
  • This replaces --uid_starts.
• Change --collection_ids/COLLECTION_IDS from a JSON list to an "args" list (like --uid_prefixes).

Testing

Run against dev

Issue(s)

Closes #735
Closes #743