[FEATURE]: add fromDatabase for dynamic migration

### Feature hasn't been suggested before.

- [x] I have verified this feature I'm about to request hasn't been suggested before.

### Describe the enhancement you want to request

**Current**
We have access to limited functions from "drizzle-kit/api" that make possible only limited cases of dynamic migration for an embedded database like pglite.

There is no available function to make a snapshot of the current version of database.
- this is perfect for a new empty database in memory
- not suitable for the same database stored as a file : drizzle-kit is not available at runtime

```typescript
private async genPgMigration(fromSchema: Record) {
const prev = generateDrizzleJson({});
const cur = generateDrizzleJson(fromSchema);
return generateMigration(prev, cur);
}

private async applyPgMigration(migrations: string[]) {
for (const migration of migrations) {
try {
await this.pglite.exec(migration);
} catch (e) {
console.error("🚨 Error executing migration:", migration, e);
throw e;
}
}
}
```

**Desired**
Make `fromDatabase` available to "drizzle-kit/api", so that it is possible to migrate on demand from the current state of the database to the new one, without relying on the json migration files.