feat: move sso and ldap logins into plugins (C2)

drizzle/postgres/0053_keen_thanos.sql

@@ -0,0 +1,4 @@
+-- sso_providers moves to the sso plugin's adopted table at activation, and
+-- its LDAP rows are copied into the ldap plugin by a boot migration after
+-- this runs. Dropping it here would lose the data first.
+SELECT 1;