The issuer runs.  Helpers to poke the right API calls into the right place
forthcoming...

Add an end-to-end system test for Tahoe-LAFS storage interaction.

just need 35 more hosts and then defining the function will be a win ...

Also improve failure reporting.

Support configuration for the issuer location.

Depend on ZKAPAuthorizer's overlays for anything ZKAPAuthorizer requires.

It knows better than we do about its own dependencies.  Let it control them.

It is better than what we have here and duplicating it is sad.  ZKAPAuthorizer
also has much tighter binding to Tahoe-LAFS version than anything in this
repository so it makes sense to let it dictate that detail.

Also bump the version being used.  This will be important in a minute.

Add NixOS and morph configuration for the testing and production grids.

Configurable public address

100TB NixOS configuration

Also open the firewall!  Yea.  That is a pretty important thing.

There will be no staging grid and the other two nodes in this grid went
elsewhere.

Define testing grid and production grid with a function they can share.

There is not going to be a staging grid.
There will be a testing grid and a production grid.
The testing grid will be loosey goosey.
The production grid will have incremental rollouts.