sqldb: ensure schema definitions are fully SQLite compatible

Previously, we applied replacements to our schema definitions
to make them compatible with both SQLite and Postgres backends,
as the files were not fully compatible with either.

With this change, the only replacement required for SQLite has
been moved to the generator script. This adjustment ensures
compatibility by enabling auto-incrementing primary keys that
are treated as 64-bit integers by sqlc.

sqldb/sqlc/migrations/000003_invoice_events.up.sql

@@ -29,7 +29,7 @@ VALUES
 -- AMP sub invoices. This table can be used to create a historical view of what
 -- happened to the node's invoices.
 CREATE TABLE IF NOT EXISTS invoice_events (
-    id BIGINT PRIMARY KEY,
+    id INTEGER PRIMARY KEY,
 
     -- added_at is the timestamp when this event was added.
     added_at TIMESTAMP NOT NULL,