Move SQL stuff to sqlbuilder.

internal/sqladapter/database.go

internal/sqladapter/result.go

internal/sqladapter/testing/adapter.go.tpl

internal/sqladapter/testing/adapter_benchmark.go.tpl

internal/sqladapter/tx.go

postgresql/database.go

postgresql/postgresql.go

postgresql/tx.go

sqlbuilder/builder.go

sqlbuilder/delete.go

sqlbuilder/insert.go

sqlbuilder/interfaces.go

sqlbuilder/select.go

sqlbuilder/sql.go

sqlbuilder/update.go

wrapper.go