Update perfect-scrollbar to fix stutter space-scrolling in #8544. Also
reworked deprecated `element.perfectScrollbar` to `new
PerfectScrollbar(element)`. Lastly, updated provision version and
changed node module path to new path.
This also refactors perfect-scrollbar in help.js to work with updated
version of perfect-scrollbar. Because the update also changed
perfect-scrollbar's css selectors for all scrollbars in zulip, we
update those too.
Fixes#8544.
In addition to decreasing the excessive number of bundles we had, this
will set us up to fix rendering of code blocks when clicking the
sidebar links in the /api-new site.
This creates a dropdown in place of the normal register/login links
you get when logged out, with an option to go to the app or log out if
that appears you click on the avatar.
A bit more work is needed to make this look really good, but it's a
great start.
This redesigns the /help/ page sets to be a single page app that uses
history.pushState to work the same as the old app.
The big new feature is that now we have the index in a nicely designed
left sidebar.