Update .gitignore to reflect directory structure changes

Also removed some unused ignore lines.

Eliminate "conservancy" and "apps" subdirectories

The directory nesting is unnecessary here and confusing to navigate. I've moved
all apps to the project subdirectory, currently called "www", but soon to be
renamed "conservancy".

I've also moved manage.py to the top-level directory.

Add Use the Source mockup pages

This doesn't include any data models yet.

Allow "outercontent" template block to use full page width

This allows us to create full-width layouts for specific campaigns.

Remove unused modpythoncustom.py

We have used mod-wsgi for many years.

Fix podjango migrations

Required an updated following code restructuring.

Switch to relative imports

The relative imports make it clearer what code is within the project and where
it's coming from.

podjango: Factor out credits, feedback and license info

This makes it easier to keep up-to-date across multiple templates.

podjango: Link up "The Corresponding Source" title

This helps with navigating back to the home page.

Merge podjango.apps.cast into main podjango module

It's much simpler if "podjango" is the name of the Django app with a single
urls.py etc. The reason this is required is because podjango was originally a
fully-blown Django website and now it's become a Django app within the
Conservancy website.

Remove www/conservancy/static/admin

These files are copies from an old version of Django, causing display issues in
the newer Django admin. With the "staticfiles" app enabled, the recent versions
of these files are copied to /var/www/website/collected-static/ when you run the
"collectstatic" management command. For example:

sudo -u www-data /var/www/venv-website/bin/python manage.py collectstatic --link

assignment: Prevent unhandled error when fields not provided

This typically happens when a bot is submitting the form. This should be a
validation error rather than an unhandled exception.

Rename cast to "The Corresponding Source", move to URL prefix "/cast/"

Also improved detail view rendering where unclosed <ul> tags in the body
content HTML from the database were affecting the display of footer info.

Don't serve tachyons from staticfiles just yet

We need to consolidate the static files all at once.

Merge FAIF "podjango" codebase into main sfconservancy.org site

It's a little awkward for now with podjango also having an "apps" module, but we
can clean that up later. I've excluded any JS and HTML that's likely not
required.

To accomodate this merging, I moved the templates into a "podjango" subdirectory
and, added a "podjango" namespace to the URLconf and converted a bunch of
hard-coded links to use the "url" template tag since there will now be a
"/faif/" prefix.

Move TEMPLATES, AUTHENTICATION_BACKENDS and MIDDLEWARE into base settings

These don't change, so belong in the base settings.

Update ALLOWED_HOSTS for new server

There's no need for the site to be accessed via IP or it's hostname.

Remove documentation reference to unused `djangopw` module

Code appears to have been removed some time back.

Add support for Debian Bullseye

Added `on_delete` attributes, updated ForceCanonicalHostnameMiddleware for
compatibility and added Dockerfile for Bullseye.

Add Debian Buster dockerfile

Runs fine on Buster!

Red Hat last donated to SFC on 2020-03-27.

The logo should have been removed sooner, but they kept saying they
were going to donate again and never did.

A bit more width for the video, remove <p>

Ok, that was too small, try this.

Put Karen's doctorate as our featured item.

The video may not work there, but going to try it.