Stripe Checkout means using JS code provided by Stripe to handle
almost all of the UI, which is great for us.
There are more features we should add to this page and changes we
should make, but this gives us an MVP.
[greg: expanded commit message; fixed import ordering and some types.]
This is an incomplete cleaned-up continuation of Lisa Neigut's push
notification bouncer work. It supports registration and
deregistration of individual push tokens with a central push
notification bouncer server.
It still is missing a few things before we can complete this effort:
* A registration form for server admins to configure their server for
this service, with tests.
* Code (and tests) for actually bouncing the notifications.
This feature has been obsolete since when Zulip was released as open
source software, since it's purpose was to avoid putting a "server
url" prompt in the desktop app, and now that prompt is required
anyway.
When we refactored zilencer to use a single urls.py file in
bf50dd7771, we accidentally lost the
prefix on the API urls.
This broke sending error report emails if zilencer was enabled.
For a long time, rest_dispatch has had this hack where we have to
create a copy of it in each views file using it, in order to directly
access the globals list in that file. This removes that hack, instead
making rest_dispatch just use Django's import_string to access the
target method to use.
[tweaked and reorganized from acrefoot's original branch in various
ways by tabbott]
The previous separated-out configuration wasn't helping us, and this
makes it easier to make the extra installed applications pluggable in
the following commits.