Following the issue #23380 and PR #25038, this commit changes all
occurences of `uri` into `url` in all comments, local variables,
handlebars templates (.hbs) function names and their callers in
all `.js` and `.ts` files.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>