This removes all of the global loggers from the project and replaces them with loggers which are instantiated in vspd.go and passed down as params.
To support this, the background package was removed. It only contained one file so it was a bit pointless anyway. It only existed so background tasks could have their own named logger.
While removing the globals from background.go it also made sense to clean up the use of dcrd RPC clients. Previously two seperate clients were maintained, one for making RPC calls and one for receiving notifications. These clients have been unified.
- Rename all instances to "shutdownCtx" to be really explicit. This context is special in that it can be closed at any time without warning, so it should be obvious to the reader.
- Don't use shutdownCtx in RPC clients. Clients should not stop working immediately when shutdown is signalled, they need to keep working while the process is shutting down.
- Fee tx status is now tracked using a dedicated field, with values none/received/broadcast/confirmed/error.
- Fee tx hex and hash are now both set in /payfee. The absense of txhash is no longer used to determine if a fee tx has been broadcast or not.
- setvotechoices can no longer be called before a fee is received.
- Remove `binding:required` from response types. It has no effect on responses, it is only needed on request types which are validated by gin.
* Delay fee broadcast and adding tickets to wallets.
- Adds a `background` package which implements a dcrd notification handler. On each blockconnected notification, tickets with 6+ confirmations are marked confirmed, relevant fee transactions are broadcast, and any fees with 6+ confirmations have their tickets added to voting wallets.
- VSP fee is now an absolute value measured in DCR rather than a percentage. This simplifies the code and is more appropriate for an MVP. We can re-add percentage based fees later.
- Database code for tickets is now simplified to just "Insert/Update", rather than having functions for updating particular fields.
- Pay fee response no longer includes the fee tx hash, because we dont necessarily broadcast the fee tx straight away.
* Const for required confs
