fix(services): prevent adding volume without source and target (#4538)

* feat(services): check that target mounts are non empty

* feat(services): prevent creating service when no source

* refactor(services): remove ng-form

* fix(services): check that every volume is valid

app/assets/css/app.css

@@ -1042,3 +1042,7 @@ json-tree .branch-preview {
   background-color: #337ab7;
 }
 /* !spinkit override */
+
+.w-full {
+  width: 100%;
+}