Installer: Simplify volume usage API

Change-Id: I4a7189af9194c70a6c5aac96d39618a6827965bd
diff --git a/core/installer/values-tmpl/zot.cue b/core/installer/values-tmpl/zot.cue
index 0c63c76..cd0feca 100644
--- a/core/installer/values-tmpl/zot.cue
+++ b/core/installer/values-tmpl/zot.cue
@@ -46,21 +46,9 @@
 		branch: "main"
 		path: "charts/zot"
 	}
-	volume: {
-		kind: "GitRepository"
-		address: "https://github.com/giolekva/pcloud.git"
-		branch: "main"
-		path: "charts/volumes"
-	}
 }
 
-volumes: {
-	zot: {
-		name: "zot"
-		accessMode: "ReadWriteOnce"
-		size: "100Gi"
-	}
-}
+volumes: zot: size: "100Gi"
 
 _httpPort: 80
 
@@ -105,9 +93,4 @@
 			startupProbe: {}
 		}
 	}
-	volume: {
-		chart: charts.volume
-		info: "Creating disk"
-		values: volumes.zot
-	}
 }