…ve to immutable tags for deployment (#192)

…9) (#194)

Create a new modal div that contains the uplift request form. Add a new
button for requesting uplifts next to the "Preview Landing" button.
Remove the code that allows pressing the "Preview Landing" button
even when the stack is not landable since we no longer have the
uplift button behind that modal.

…lable (Bug 1888188) (#198)

As part of the checks refactor we will eventually support displaying
multiple blockers in the front end. Add a shim so Lando-UI can handle
output from before and after the refactor PR in LandoAPI is landed
and deployed.

Implement a Treestatus UI in Lando. All endpoints in the new
interface are namespaced under `/treestatus`. The main components
are as follows.

The main Treestatus page displays all trees and their current statuses.
When authenticated, each tree can be selected for updating via a checkbox,
or a "select all trees" button is available for CI-wide tree closures.
The tree selections are forwarded to the update form when "Update trees"
is selected.

The "update trees" view implements a form for updating the status of
trees. Trees can be set to open, closed and "approval required". When
the status is being set to a non-open state, a reason and reason
category must be specified. The form presents a "remember this change"
option which can be used to easily revert the change at a later time.
For example if all trees are closed, the trees can be mass re-opened
easily.

The individual log view of a tree presents the most recent status
updates for each individual tree. When authenticated, users can edit
the tree status reason or category in case of a typo or error during
submission by clicking the "edit" button, which toggles the display to a
form for updating.

The recent changes view is a header that appears for authenticated users
on all pages. It presents all status updates that have been "remembered"
during update. Users can edit the reason and reason category using an
"edit" button that toggles the display to a form. The "restore" button
can be used to revert the status change. The "discard" button can be
used to throw away the status change if it is no longer necessary to
remember the change.

The Treestatus UI uses message flashing and the existing Lando-UI
notifications component to present errors and action verification to the
user.

)

…r key (Bug 1888188) (#199)

In the original revision I added a `blocked_reason` variable to avoid repeated
code, however I forgot to update the template to actually use the variable.

…calls (Bug 1896642) (#203)

In other parts of Lando, before making an API call that uses
the `require_auth0` kwarg, we do an explicit check that the
user is authenticated and handle unauthenticated requests
appropriately. This was overlooked in implementing the Treestatus
UI and is resulting in errors in Sentry since we instead
only discover the missing credentials when making the request,
resulting in an unhandled exception. Add an explicit check
to each handler which makes an `auth0_required` API call.

…202)

When calling out to the tree logs endpoint, we do not properly
handle non-2XX reponse codes within LandoUI, as those throw a
`LandoAPIError` which must be handled. Add a `try/except` block
around the error to properly handle tree names that return 404
from LandoAPI and other errors.

…(Bug 1897044) (#204)

The `error` and `exception` level logging calls cause Sentry to treat
expected states as new issues. Lower the level to `info` to quiet down
Sentry. Issues experienced by the Treestatus API will still show up in
the LandoAPI logs, and at the `info` level we can still debug which
code paths are taken by various requests.

…rs (Bug 1901484) (#205)

Add a new `is_treestatus_user` template helper which checks for
membership in the Treestatus Mozillians groups. Switch to using
this new function to determine if Treestatus editing elements of
the UI should be shown.