Pull request 2111: 6545-schema-version

Updates #6545.

Squashed commit of the following:

commit b1969128a99ff21c97feb4e7805b4b8133d7122f
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 15 20:04:37 2023 +0300

    home: fix import

commit 872ccea1491a8da76cc24db79247438d0ce4d256
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 15 20:01:15 2023 +0300

    all: output schema version

internal/configmigrate/v4.go

@@ -0,0 +1,30 @@
+package configmigrate
+
+// migrateTo4 performs the following changes:
+//
+//	# BEFORE:
+//	'schema_version': 3
+//	'clients':
+//	- # …
+//	# …
+//
+//	# AFTER:
+//	'schema_version': 4
+//	'clients':
+//	- 'use_global_blocked_services': true
+//	  # …
+//	# …
+func migrateTo4(diskConf yobj) (err error) {
+	diskConf["schema_version"] = 4
+
+	clients, ok, _ := fieldVal[yarr](diskConf, "clients")
+	if ok {
+		for i := range clients {
+			if c, isYobj := clients[i].(yobj); isYobj {
+				c["use_global_blocked_services"] = true
+			}
+		}
+	}
+
+	return nil
+}