Remove the project level overview template

Removes the old overview template, this
has now been moved into a vue file.

Removes the associated CSS

app/assets/stylesheets/pages/cycle_analytics.scss

@@ -360,23 +360,3 @@
     }
   }
 }
-
-.cycle-analytics-overview {
-  padding-top: 100px;
-
-  .overview-details {
-    display: flex;
-    align-items: center;
-  }
-
-  .overview-image {
-    text-align: right;
-  }
-
-  .overview-icon {
-    svg {
-      width: 365px;
-      height: 227px;
-    }
-  }
-}

app/views/projects/cycle_analytics/_overview.html.haml

-.cycle-analytics-overview
-  .container
-    .row
-      .col-md-10.offset-md-1
-        .row.overview-details
-          .col-md-6.overview-text
-            %h4 Introducing Value Stream Analytics
-            %p
-              Value Stream Analytics (VSA) gives an overview of how much time it takes to go from idea to production in your project.
-              To set up VSA, you must first define a production environment by setting up your CI and then deploy to production.
-            %p
-              %a.btn{ href: help_page_path('user/analytics/value_stream_analytics.md'), target: '_blank' } Read more
-          .col-md-6.overview-image
-            %span.overview-icon
-              = custom_icon ('icon_cycle_analytics_overview')