Project setup friction

[thibaudcolas]

From my own experience and feedback from @eigenwijsje setting up the site for work on #405,

• Was confusing that the tests require having run collectstatic. Not sure if this is a must for us?
• Going though the manual setup felt like the simplest option. Perhaps worth streamlining the Docker setup?
• Docker setup doesn’t have Docker Compose, so no volumes, so right now requires a lot of container rebuilding
• compilemessages: CommandError: Can't find msgfmt. Make sure you have GNU gettext tools 0.15 or newer installed.. This is so rarely needed that it really shouldn’t be a req for most of the setup.