Group choices for scheduling a job by day

The options for scheduling a job by time should be grouped by day,
because a long list of 96 options is not very usable.

On the server side, this commit generates label for the next 4 days in
a friendly format (ie today/tomorrow/Sunday/Monday)

The Javascript component for choosing a time was built in a kind of
old-school jQuery way, where it manipulated the elements on the page.
The complexity of introducing groups of options was just too much for
this pattern, because it involves storing a lot of state in the DOM.

This commit completely rewrites the JS to:

- read the initial options and groups from the HTML and store them
  in the object
- use Hogan to completely re-render the UI from a series of Mustache
  templates, each of which represents a state of the UI and takes the
  inital options and groups
- filter the choices to show when the today/tomorrow/… buttons are
  clicked

app/assets/stylesheets/components/radio-select.scss

@@ -6,7 +6,9 @@
     vertical-align: top;
 
     .block-label {
-      margin-right: 10px;
+      margin-right: 5px;
+      padding-right: $gutter - 10px;
+      padding-left: 54px - 10px;
     }
 
   }
@@ -15,33 +17,12 @@
     display: inline-block;
     vertical-align: top;
     width: auto;
-    padding: 20px 30px 15px 30px;
+    padding: 20px $gutter-half 15px $gutter-half;
+    margin-right: 5px;
   }
 
   .js-enabled & {
 
-
-    .block-label {
-      &:last-child {
-        margin-bottom: 10px;
-      }
-    }
-
-    .block-label,
-    .tertiary-button {
-      display: none;
-    }
-
-    .js-visible {
-
-      display: block;
-
-      &.tertiary-button {
-        display: inline-block;
-      }
-
-    }
-
   }
 
 }