Add appendix pages to search

[jimbonothing64]

Proposed changes

fixes #1824
Add appendix pages to the search feature. The pages contributors, about and sitemap will show up in the search -- with a relatively low weighting.
Changes:

• Appendices are now stored in the database
• Appendices are indexed for search by their name, and text content (from template)
• Appendices loader now loads appendices into the DB
• Existing tests for appendix app re-enabled and updated
• Tests for appendix model
• Tests for get_template_text function
• Tests for appendix loader

[JackMorganNZ]

@jimbonothing64 If you need help getting this working, I'm happy to take a look at it sometime.

[jimbonothing64]

@jimbonothing64 If you need help getting this working, I'm happy to take a look at it sometime.

Thanks @JackMorganNZ !

I've been blocked by other work for the last month (likely the next ~2 weeks too). Getting the dev staging CD deploying again is the next priority. I chose this issue for good tour of the project -- it's not my urgent list.

I'm a month out of touch, but from memory, the main area was familiarizing myself with the loader testing setup. Perhaps you've spotted something else, however. If you want to and have the time, it would be instructive if you had any advice/pointers -- but understandable if not!

Thanks again.