In this commit, all the sql, non-postgres-specific, code is moved out of
the postgres package and into a new sqlbase package. This will make it
more easily reusable for future sql integrations.
In this commit, changes are made to the `kvdb/postgres` package so that
all all the non-postgres-specific code is generalised to be applicable
for all sql code. A follow up commit will move all the general sql code
into its own package.
Due to the update of the kvdb package to go1.18, the `// +build`
directives are no longer required. They are removed in this commit in
order to simplify upcoming commits. Along the way, a few typos are fixed
and an unused struct is removed.
Previously the assumption existed that panic data was already an error.
If that wasn't the case for example because panic("string") was used,
the transaction wasn't unlocked.
