Move from swaddle to honcho.

Allong with some cleanup of README and Makefile.

I have used `honcho`s ability to use several environment files at the same time. This way when we need to add some env var, we can just update the `default_*.env` files and be done with it - no need for all devs to go editing their files.

The changes in the README relate to #1200 where I suggest using empty string and setting up the default db so it just works.

Please test & review. Fixes #1200 and #468.