feat: add support for *sql.DB-registered Go migration

[mfridman]

Fixes #201 #386 #324

Most of this code is ported over from the large provider branch #378.

This PR adds logic to support *sql.DB-registered Go migrations. We technically do not need the function types, but I found these extremely useful. This should be backwards-compatible.

type GoMigration func(tx *sql.Tx) error
type GoMigrationNoTx func(db *sql.DB) error

The new functions to add/register migrations are:

func AddMigrationNoTx(up, down GoMigrationNoTx) { ... } 
func AddNamedMigrationNoTx(filename string, up, down GoMigrationNoTx) { ... }

• Add tests for both *sql.DB and *sql.Tx-style Go migrations

[cbodonnell]

looks good 👍

[mfridman]

looks good 👍

Thanks for your help @cbodonnell, if I find some time I'll try and capture this in a blog post over on the goose docs.

[VojtechVitek]

Nice work. Thanks @mfridman @cbodonnell 🎉

[mcosta74]

cool thanks. Any ETA for v3.9.0 ?

[mfridman]

Likely by the end of next week (if not earlier), I'd like to get a few other PR's into that release.