Implements a first try at splitting xref into batches

[TheApeMachine]

• Changes the type of the XREF_SCROLL_SIZE setting to integer.
• Adds new setting for STAGE_XREF_BATCH
• Adds above setting to Worker
• Modifies xref_collection method to enqueue in batches determined by scroll size setting

Note: I think I have made a mistake in accidentally removing a line, I added a TODO in the code. I have to quickly test things when I put it back, as I cannot guarantee things will remain in a working state if I put it back blindly now. However, I would love some feedback to understand if I am on the right track with all this :)