fix: add celery tasks for idnits2 and bibxml file generation

[russhousley]

Add celery tasks for idnits2 and bibxml file generation. Fixes #7192

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.79%. Comparing base (187c2c5) to head (02c6b33). Report is 317 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7204      +/-   ##
==========================================
- Coverage   88.98%   88.79%   -0.20%     
==========================================
  Files         291      296       +5     
  Lines       40717    41312     +595     
==========================================
+ Hits        36233    36682     +449     
- Misses       4484     4630     +146     

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[jennifer-richards]

In the scramble to cut over to the new infrastructure, I lost track of this PR and wound up reimplementing it slightly differently. I'm merging that over so we can merge this.