Allow filter links to be used in combination

Means you can see, for example emails that have failed.

Means adding:
- logic to generate links which can have a type parameter, a status
  parameter, or both
- a ‘pill’ UI component for seeing which filters you currently have
  applied
- some logic to change the page title based on which filters you have
  applied

app/assets/stylesheets/components/pill.scss

@@ -0,0 +1,41 @@
+.pill {
+
+  display: flex;
+
+  a, span {
+    display: block;
+    padding: 10px;  
+    flex-grow: 1;
+    text-align: center;
+
+    &:first-child {
+      margin-left: 0;
+    }
+
+    &:last-child {
+      margin-right: 0;
+    }
+
+  }
+
+  a {
+    background: $panel-colour;
+    color: $link-colour;
+    border: 1px solid $panel-colour;
+    position: relative;
+
+    &:hover {
+      color: $text-colour;
+    }
+
+    &:active,
+    &:focus {
+      z-index: 10;
+    }
+  }
+
+  span {
+    border: 1px solid $grey-1;
+    color: $text-colour;
+  }
+}

app/assets/stylesheets/components/table.scss

@@ -79,10 +79,6 @@
 
   p {
     margin: 0 0 5px 0;
-
-    a {
-      text-decoration: none;
-    }
   }
 
 }

app/assets/stylesheets/main.scss

@@ -48,6 +48,7 @@ $path: '/static/images/';
 @import 'components/email-message';
 @import 'components/api-key';
 @import 'components/vendor/previous-next-navigation';
+@import 'components/pill';
 
 @import 'views/job';
 @import 'views/edit-template';