dummy DaDem endpoint to make development easier

[struan]

This adds a dummy DaDem, plus GAZE and Ratty endpoint that fakes things
well enough to allow local testing without access to those services.
It's still a bit fragile but in general it works well enough when run
with Docker to allow you to do the whole thing.

Currently you have to log in to the container and start fyrqd by hand
for things to work.

The results on the candiated choice screen are somewhat unrealistic but
the point is more to let you run through the screens.

The actual script is outside the web tree and mapped in by Docker so
won't be accidentally discoverable live.

[dracos]

Fine with me; we should probably also move away from having to deploy a test on a server, but eh when do we have time for that. This seems easier than letting WTT use mocked instances or something, doesn' t it

[ajparsons]

Ok - see what you think of this. This now seems to work for me in my docker.

I've moved the packages that were needed to run fyrqd into the packages file (conversation with Sam says this currently isn't used in production, just development).

The more fiddly change was making the dadem dummy data a bit more responsive to different areas (I tried to test with london postcodes and it started throwing mismatch errors because the results being returned in the dummy data didn't line up with the areas it expected). I might have missed something more simple though.

[struan]

one small fix but this looks decent