Add O4b config.

This branch adds the O4b configs, with the main files being the 'gstlal_inspiral_postcohspiir_spiir.sub' files, and the '.dag' file that sets a couple of variables for them. The O4b folders were added in !234 (merged) as a copy of the O4a configs, so that the diff would be clearer for review.

Notes

• Currently these are based on an engineering run, using Test gracedb uploads, but I'll update these before merging.
• The O4a configs I used were from before a rollback, so there are some different args with no science effect. This includes '--finalsink-superevent-thresh' and offset args. I may update the O4a configs in git using the runs set after the rollback for a cleaner comparison.
• O4b includes Virgo, which requires more compute nodes, which increases the 'far-factor' (each node needs to scale its false alarm rate down based on the number of compute nodes).