The diffDOM Javascript sometimes throws an error if it can’t calculate
a diff between the original content of the page and the updated HTML
delivered via AJAX. The problem seems to be when there’s not one,
consistent top-level element for it to base its calculations on.
This commit:
- makes sure that all AJAX-delivered partials have a wrapping `<div>`
- that this `<div>` has a consistent class name to make it clear why
it’s there
we don't want to use the old statistics endpoints any more
also a couple of quality of life changes
* moves some logic out of the _totals.html template
* tidies up statistics_utils
Previously, the AJAX update for the dashboard was returning a big blob
of JSON with one key.
This commit splits it up to return:
- one key for each section of the page
- each containing a smaller chunk of HTML rendered from a partial
The jobs page was already working this way (pretty much) but just needed
a little tweaking to get it the same.
Previously the structure was
```
dashboard.html
|_ today.html
|_ some random html
|_ a few things split into partials
```
This commit simplifies the structure to just be:
```
dashboard.html
|_ partial
|_ partial
|_ …
```
