Build notes: better incremental loading behavior

[mathstuf]

Bug report

Expected Behavior

The build notes page (/builds/:id/notes) progressive loading should move some of the "skeleton" (list of notes and anchors) to before the first paint. This would fix two problems:

• going to a URL with a #noteXX fragment goes nowhere until the anchor exists
• with lots of note contents, the page takes a long time to render anything

Actual Behavior

Nothing (besides decorations) loads until all note contents have been loaded client-side. Instead, note contents could, ideally, be deferred until the relevant section is expanded. Usually one needs a few note contents, not all of them, when visiting this page.

CDash Version

open.cdash.org