Use obsrepositories for the CentOS 9 image

We were relying on the repos being parsed from the kiwi description but this can
cause problems and gives us less flexibility when it comes to fixing repository
setup issues.

This fixes #2335

build-tests/x86/centos/test-image-live-disk-v9/appliance.kiwi

@@ -51,23 +51,8 @@
     <users>
         <user password="$1$wYJUgpM5$RXMMeASDc035eX.NbYWFl0" home="/root" name="root" groups="root"/>
     </users>
-    <repository type="rpm-md" alias="kiwi-next-generation" priority="1">
-        <source path="obs://Virtualization:Appliances:Staging/CentOS_9"/>
-    </repository>
-    <repository type="rpm-md">
-        <source path="obs://Fedora:EPEL:9/next"/>
-    </repository>
-    <repository type="rpm-md">
-        <source path="obs://Fedora:EPEL:9/standard"/>
-    </repository>
-    <repository type="rpm-md">
-        <source path="obs://CentOS:CentOS-9:Stream/crb"/>
-    </repository>
-    <repository type="rpm-md">
-        <source path="obs://CentOS:CentOS-9:Stream/appstream"/>
-    </repository>
-    <repository type="rpm-md">
-        <source path="obs://CentOS:CentOS-9:Stream/baseos"/>
+    <repository type="rpm-md" priority="1">
+        <source path='obsrepositories:/'/>
     </repository>
     <packages type="image">
         <package name="syslinux"/>