Create basis for mastodon feeds before migrating

district/models.py

district/templates/district/base.html

...templates/district/district_interactive_program_page.html

senate/models.py

senate/templates/senate/base.html

shared/blocks.py

shared/models.py

shared/static/shared/js/mastodon_helper.js

shared/static/shared/svg/share-icons/mastodon-brands.svg

shared/templates/shared/blocks/mastodon_feed_block.html

shared/templates/shared/mastodon_feed_link_snippet.html

shared/templates/shared/mastodon_feed_snippet.html

shared/templates/shared/mastodon_icon_snippet.html

shared/templatetags/shared_filters.py

uniweb/models.py

uniweb/templates/uniweb/base.html