Update custom Navbar/Footer models & templatetags to work in multi-site
Description of change
Added a site FK field to the custom Navbar and Footer models in the pro template; added the new migration for these models; and updated the website templatetags in the pro template to work with the newly updated models.
Resolves #683 & #673
Documentation
Updated the docs the discuss how the snippets in the basic and pro templates work with multi-site installs in different ways.
Tests
Did not add tests, because there are no existing tests for the pro template website app (unless I missed something). Without an existing test suite for the website app in which to add my tests, I didn't want to make significant additions without asking the coderedcorp folks how/if I should approach this.
Nice work, thanks! We can remove that fallback code as it is not necessary and should simplify it a bit.
Tests aren't necessary here, as long as you manually tested it. The pipeline will generate a pro project and run the full battery of tests using it.
As requested.
Also, apologies for committing directly to main vice a new branch. I'm clearly a bit out of practice 😬
Looking good, left a few more comments. I think it will be ready to merge after that.