Add ability to sort of edit TOCs with authors/etc

[cdrini]

Part of #8756

Adds the new fields to a new column in the markdown as JSON. This isn't a great UI, but, more importantly, it makes it so that the extra fields aren't erased when someone edits an openlibrary record with authors/etc already in the TOC field.

Depends on #9910 .

Technical

• Add an ol-message CSS component for small messages; inspired by https://primevue.org/message/
• Add space indenting to table of contents editor for easier legilibity

Testing

• ✅ books without table of contents render correctly
  • https://testing.openlibrary.org/books/OL10324632M/STOWELL_SYSTEMS_SCIENCE
• ✅ books with "normal" table of contents render correctly
  • https://testing.openlibrary.org/works/OL27482W/The_Hobbit?edition=key%3A/books/OL27289715M
• ✅ books with "normal" table of contents don't show warning
• ✅ books with table of contents + extra fields render correctly
  • https://testing.openlibrary.org/books/OL9462467M/Great_Irish_Stories_of_Childhood
• ✅ books without table of contents can be edited/saved
• ✅ books with "normal" table of contents can be edited/saved
• ✅ books with table of contents + extra fields can be edited/saved

Screenshot

Stakeholders

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 17.05%. Comparing base (ce16a79) to head (e1e5029).
Report is 453 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9915      +/-   ##
==========================================
+ Coverage   16.06%   17.05%   +0.99%     
==========================================
  Files          90       89       -1     
  Lines        4769     4725      -44     
  Branches      832      829       -3     
==========================================
+ Hits          766      806      +40     
+ Misses       3480     3409      -71     
+ Partials      523      510      -13     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.