templates: remove Server: and Repo: in list images

Although ogcp support for multiple server, the plan is to only support for one
server in this version.

Remove Server: context information and Repo: in list images

ogcp/templates/actions/list_images.html

@@ -7,9 +7,8 @@
 
 <h1 class="m-5">{{_('List images')}}</h1>
 {% for server in servers %}
-    <h3 class="mx-5">Server: {{server['name']}}</h3>
     {% for repo, images in server['repos'] %}
-    <h4 class="mx-5">Repo: {{repo}}</h4>
+    <h4 class="mx-5">{{repo}}</h4>
         <table class="table table-hover mx-5">
         <thead class="thead-light">
             <tr>