This allows both tspend and treasury policies to be set by clients on a per-ticket basis. Preferences can be set when initially registering a ticket with `/payfee`, and can be later updated using `/setvotechoices`.
Any requests which alter treasury/tspend policy will be stored in the database using the existing accountability system.
**Note:** This does not include consistency checking, it will need to be added later when dcrwallet has an RPC to retrieve policies in batches.
* Remove static cfg values from GUI cache.
Theres no need for these values to be copied into the cache when templates could simply access the config struct directly.
This also changes the cache accessor so it returns a copy of the cache rather than a pointer, which removes a potential race.
* Rename and move cache.
Cache code was previous in `homepage.go`, but its used in multiple places and not just on the homepage. Its enough code to go into its own dedicated `cache.go`.
- Use bootstrap to improve layout.
- Add warning banners for webserver debug mode and vspd closed.
Admin page:
- Replace listing of all tickets with form to search by ticket hash
