We now render the "skin" part of "Stream Settings" before
adding in the actual streams. The new function
populate_stream_settings_left_panel() takes care of adding
the streams. It uses a new template called
`subscriptions.handlebars`.
Splitting out this function will give us more flexibility
for various improvements.
First, we can decide to render the list after we open the
overlay, just to avoid the problem that users don't know why
the modal's opening. (And we could add a loader spinner as
needed.)
Second, we can improve our filter features so that we do
filtering in the data instead of moving DOM rows around,
which is expensive.
Third, we can eventually introduce progressive rendering.
Finally, having the function broken out will make profiling
more precise about where bottlenecks exist.
We used to render the subscriptions_settings template for every
stream when you loaded "Manage Streams," which can be very slow
for a big realm. Now we only render the right pane on demand.
This makes the subscriptions page responsive by having the settings tab
slide over when a user taps on a stream, giving almost the whole screen
to view the settings.
This is a major change to the /#subscriptions page, converting it to
by a side-by-side list of streams and their settings in an overlay.
There are no new features added/removed, but it's a huge changeset,
because it replaces the old navigation logic and moves the stream
creation modal to appear in the right side of this overlay.
Filter behaves similarly to filter in left sidebar, see PR #684. Added
stream input field to the stream creation modal along with other settings,
for clarity.
Fixes#455, #563.
If a user is not allowed to create new streams, then do not
show the "Create new stream" UI at the top of the settings page.
(imported from commit b97626938d8b612317c2189f7eca0d4bd27fc274)