[Pg] Fix many introspection issues

[L-Mario564]

Addresses #1210, #1928, #1625, #2315, #2714, #1633, #1648.

This PR aims to fix many introspection issues for the PG dialect in Drizzle Kit.

Summary of fixes

• Handle sql values:

id: integer("id").default(nextval('deal_id_seq'::regclass)).primaryKey().notNull(); // Current
id: integer("id").default(sql`nextval('deal_id_seq'::regclass)`).primaryKey().notNull(); // Fix

• Wrap string in quotes if the column name is an invalid object key:

top:detected: tinyint("Top:detected"); // Current
'top:detected': tinyint("Top:detected"); // Fix

• Handle default null:

create table "users" ( "phone" text default null::text );

phone: text("phone").default(NULL::text); // Current
phone: text("phone"); // Fix

• Correctly reference enums in different schemas:

const auth = pgSchema("auth");
const aalLevelInAuth = auth.enum("aal_level", ['aal1', 'aal2', 'aal3']);

aal: aalLevel("aal"); // Current
aal: aalLevelInAuth("aal"); // Fix

• Fix enums "overlapping" with native types:

const timeLeft = pgEnum("TimeLeft", ['VERY_LONG', 'SHORT', 'MEDIUM', 'LONG']);

timeLeft: time("timeLeft").notNull(); // Current. This happens because the enum began with "time" and the native "time" got picked up instead
timeLeft: timeLeft("timeLeft").notNull(); // Fix

[AndriiSherman]

Thanks! I fixed most of the same issues yesterday, so I'll merge your PR and find the places where we have common fixes and what you additionally fixed

[AndriiSherman]

I'll close this one as long as it had a lot of conflicts with another implementation that was fixed. I took some ideas from this PR, like removing "::" mappings in introspect and some array type default handlers

I didn't merge it, because it would have caused more problems and taken more time to resolve

Thanks a lot for you work