As we've now switched over to using sqldb v2 for most of the db objects,
we can remove a lot of deprecated code that's no longer used in the litd
project. This commit removes that code.
The upcoming implementation of `sqldb/v2` will extensively create
a `Queries` object on the fly. To make more intuitive how to create
the queries object for specific database types, we introduce a
`NewForType` helper method.
This also mimics how `tapd` creates the `Queries` object, and in order
not let `litd` have it's own definition of how `Queries` object are
created on the fly, the upcoming `sqldb/v2` usage will utilize this
helper method.
The `sqldb/v2` package now provides a definition for the `BackendType`
type. As useage of `sqldb/v2` requires useage of that type, we update
`litd` to use the `BackendType` definition from `sqldb/v2`, instead of
it's own definition.
Here, we manually define some queries for the actions store. We do this
so that we can manually build the "SELECT" and only add "WHERE" clauses
that are actually needed for the query and hence ensure that available
indexes are used.
This commit adds the boilerplate code we will need in order to start
using SQL backed stores (namely sqlite and postgres) for our DB backend.
NOTE that this has been copied from the taproot-assets repo.
