Move SQL migrations out of line

It makes them much easier to reason about, and allows other SQL tooling
to operate on them like language servers, formatters, etc.

I also brought back the removed migrations such that we can more easily
understand what they were. I included a "-- SKIP" comment describing why
those migrations are now skipped. We no longer skip migrations by
checking if it is empty, but instead check to see if the migration
starts with "-- SKIP".

compute_tools/src/migrations/0000-neon_superuser_bypass_rls.sql

@@ -0,0 +1 @@
+ALTER ROLE neon_superuser BYPASSRLS;

compute_tools/src/migrations/0001-alter_roles.sql

@@ -0,0 +1,18 @@
+DO $$
+DECLARE
+    role_name text;
+BEGIN
+    FOR role_name IN SELECT rolname FROM pg_roles WHERE pg_has_role(rolname, 'neon_superuser', 'member')
+    LOOP
+        RAISE NOTICE 'EXECUTING ALTER ROLE % INHERIT', quote_ident(role_name);
+        EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' INHERIT';
+    END LOOP;
+
+    FOR role_name IN SELECT rolname FROM pg_roles
+        WHERE
+            NOT pg_has_role(rolname, 'neon_superuser', 'member') AND NOT starts_with(rolname, 'pg_')
+    LOOP
+        RAISE NOTICE 'EXECUTING ALTER ROLE % NOBYPASSRLS', quote_ident(role_name);
+        EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' NOBYPASSRLS';
+    END LOOP;
+END $$;

compute_tools/src/migrations/0002-grant_pg_create_subscription_to_neon_superuser.sql

@@ -0,0 +1,6 @@
+DO $$
+BEGIN
+    IF (SELECT setting::numeric >= 160000 FROM pg_settings WHERE name = 'server_version_num') THEN
+        EXECUTE 'GRANT pg_create_subscription TO neon_superuser';
+    END IF;
+END $$;

compute_tools/src/migrations/0003-grant_pg_monitor_to_neon_superuser.sql

@@ -0,0 +1 @@
+GRANT pg_monitor TO neon_superuser WITH ADMIN OPTION;

compute_tools/src/migrations/0004-grant_all_on_tables_to_neon_superuser.sql

@@ -0,0 +1,4 @@
+-- SKIP: Deemed insufficient for allowing relations created by extensions to be
+--       interacted with by neon_superuser without permission issues.
+
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO neon_superuser;

compute_tools/src/migrations/0005-grant_all_on_sequences_to_neon_superuser.sql

@@ -0,0 +1,4 @@
+-- SKIP: Deemed insufficient for allowing relations created by extensions to be
+--       interacted with by neon_superuser without permission issues.
+
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO neon_superuser;

compute_tools/src/migrations/0006-grant_all_on_tables_to_neon_superuser_with_grant_option.sql

@@ -0,0 +1,3 @@
+-- SKIP: Moved inline to the handle_grants() functions.
+
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON TABLES TO neon_superuser WITH GRANT OPTION;

compute_tools/src/migrations/0007-grant_all_on_sequences_to_neon_superuser_with_grant_option.sql

@@ -0,0 +1,3 @@
+-- SKIP: Moved inline to the handle_grants() functions.
+
+ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL ON SEQUENCES TO neon_superuser WITH GRANT OPTION;

compute_tools/src/migrations/0008-revoke_replication_for_previously_allowed_roles.sql

@@ -0,0 +1,13 @@
+-- SKIP: The original goal of this migration was to prevent creating
+--       subscriptions, but this migration was insufficient.
+
+DO $$
+DECLARE
+    role_name TEXT;
+BEGIN
+    FOR role_name IN SELECT rolname FROM pg_roles WHERE rolreplication IS TRUE
+    LOOP
+        RAISE NOTICE 'EXECUTING ALTER ROLE % NOREPLICATION', quote_ident(role_name);
+        EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' NOREPLICATION';
+    END LOOP;
+END $$;