In particular, the docs now talk about the CSRF protection. This is
increasing relevant as we start having more mutation endpoints. And
make the signals api expect a csrf for session auth to match the newer
users api.
This is useful for e.g. deciding whether or not to present the user
admin UI in navigation.
As part of this change, I adjusted the casing in Permissions, and then
all the toml stuff for consistency. Noted in changelog.
Now you can set a password for a user while the server is running,
e.g. via the following command:
```shell
curl \
-H 'Content-Type: application/json' \
-d '{"update": {"password": "asdf"}}' \
--unix-socket /var/lib/moonfire-nvr/sock \
http://nvr/api/users/1
```
