perf: batch delete in chunks of 50

[iBotPeaches]

This now works as follows:

• Requests text output, broken by newline so we can easily bash split
• Starts a loop and works up to chunk size before issuing delete
• Uses a small chunk size at present (50) because anything larger makes it real tough to see what is going on
• Supports cleaning up an delete if not divisible by 50
• Still supports dry run