Generated by `pyupgrade --py3-plus --keep-percent-format` on all our
Python code except `zthumbor` and `zulip-ec2-configure-interfaces`,
followed by manual indentation fixes.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
This adds a new realm_logo field, which is a horizontal-format logo to
be displayed in the top-left corner of the webapp, and any other
places where we might want a wide-format branding of the organization.
Tweaked significantly by tabbott to rebase, fix styling, etc.
Fixing the styling of this feature's loading indicator caused me to
notice the loading indicator for the realm_icon feature was also ugly,
so I fixed that too.
Fixes#7995.