Adds type "embedded bot" to bot creation menu. Lets
users select a bot to run from a list of bots.
Currently, this list is hard-coded into the backend.
This commit add $.create(), which allows you to create a
jQuery object that just has a name to identify it, as opposed
to some selector or HTML fragment. It's useful for things that
are really used as stubs.
This also fixes a bunch of the existing tests to use $.create().
Before this fix, you could actually just do $('some-stub'), but
now we enforce that the input to $() looks like a valid selector
or HTML fragment, and we make some exceptions for things like
window-stub and document-stub.
Flaskbotrc is a file containing config of all active
outgoing webhook bots. It is used to provide configuration
of all active outgoing webhook bots to zulip-bot-server.