add API logic to promote book

[elfkuzco]

Changes

• add functions to compute actions needed to move book from current location to prod
• add function to apply selected actions needed to move book from current location to prod

[elfkuzco]

Even after applying actions, i'm not sure how to ignore some issues because even though books are re-processed, it sill flows through process_book. Do we want to ignore some issues like media_count, etc?

[codecov]

Codecov Report

❌ Patch coverage is 87.16216% with 19 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.12%. Comparing base (19a56da) to head (8605a17).

Files with missing lines	Patch %	Lines
backend/src/cms_backend/db/book_actions.py	86.20%	8 Missing and 8 partials ⚠️
backend/src/cms_backend/api/routes/books.py	72.72%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #405      +/-   ##
==========================================
+ Coverage   80.82%   81.12%   +0.30%     
==========================================
  Files          62       63       +1     
  Lines        3494     3630     +136     
  Branches      383      418      +35     
==========================================
+ Hits         2824     2945     +121     
- Misses        553      560       +7     
- Partials      117      125       +8     

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