orm: extract orm package from appview #875

This PR is only about code organization right? Seems good to me.

About migration logic, how do you think about using up/down style migrations by maybe using external tools? We can still use our own ORM but migration helpers like goose/v3 or migrate/v4 seems useful.

not entirely convinced yet that something like migrate/v4 adds a lot of value. the onus is still on the developer to write idempotent migrations (i.e., if an up migration adds a column, the down migration should remove it, and the library does not really assist in ensuring this property).

This PR is only about code organization right? Seems good to me.

but yes, this is only for organization, i want to be able to write migrations for knotserver and spindle + be able to use the query builder as well.