renamed isAdmin to isGrafanaAdmin to make it less confusable with admin role

src/app/partials/sidemenu.html

@@ -34,7 +34,7 @@
 	<a class="pro-sidemenu-link" href="account/apikeys">
 		<i class="fa fa-key"></i>API Keys
 	</a>
-	<a class="pro-sidemenu-link" href="admin/accounts" ng-if="grafana.user.isAdmin">
+	<a class="pro-sidemenu-link" href="admin/accounts" ng-if="grafana.user.isGrafanaAdmin">
 		<i class="fa fa-institution"></i>Admin
 	</a>
 	<a class="pro-sidemenu-link" href="login?logout">