The new Licenses page now triggers update checks for licenses on load.

This process involves:


POSTing to the Licenses page with a request for a license check.
The License Provider will either provide an opaque payload that can

 be used for communicating with an external licensing server, or a

 flag stating that checks aren't supported.


POSTing to the licensing server with the payload.


POSTing back to the Licenses page with the response from the

   licensing server.
The License Provider will process the result, which may involve

 installing a new license or altering the current one.


This whole process is designed to keep the details of any license

updates internal to the License Provider and licensing server. The

state is communicated in the UI, and the license information reloaded

from new attributes provided in the License Provider responses.
Along with this, licenses can be manually updated, if specified in the

license information. When enabled, this will show a button for uploading

a license, which will pop up a file chooser. After selecting a file, the

contents will be sent to the License Provider for processing via a POST

to the Licenses page.
The view for the Licenses page handles all POST requests. It requires a

CSRF token and some identifying information on the action, action target

(license provider and license), and arguments. It then dispatches to the

License Provider and handles any responses or error results.
Right now, there are specific actions that are supported by this view.

The longer-term plan is to enable arbitrary action support, so License

Providers can trigger custom behavior automatically or in response to

user actions.

All Python and JavaScript unit tests pass.
Tested manually uploading valid and invalid licenses for Power Pack

(ported to the new architecture), verifying the results.
Tested automatic license updates for Power Pack.
Tested all error results and display.