db/sqlc: kvstores schemas & queries

In this commit, we define the schemas and queries that are needed to
implement the firewalldb's KVStores in SQL.

Author: ellemouton

db/migrations.go

@@ -22,7 +22,7 @@ const (
 	// daemon.
 	//
 	// NOTE: This MUST be updated when a new migration is added.
-	LatestMigrationVersion = 2
+	LatestMigrationVersion = 3
 )
 
 // MigrationTarget is a functional option that can be passed to applyMigrations

db/sqlc/kvstores.sql.go

@@ -0,0 +1,7 @@
+-- Drop indexes first.
+DROP INDEX IF EXISTS kvstores_lookup_idx;
+
+-- Drop tables in reverse dependency order.
+DROP TABLE IF EXISTS kvstores;
+DROP TABLE IF EXISTS features;
+DROP TABLE IF EXISTS rules;