Instead of storing the cached manager info in the Blender preferences,
store the info in a JSON file. The file is located in the user prefs
folder (`~/.config/blender/{version}/config` on Linux).
This also reduces the number of 'refresh' operators to a single one, which
then fetches all necessary info from the Manager.
This fixes an issue (reported via chat) where worker tags were sometimes
not retained across file saves.
Implement the `getSharedStorage` operation in the Manager, and use it in
the add-on to get the shared storage location in a way that makes sense
for the platform of the user.
Manifest task: T100196
Before submitting a job, the add-on now checks the version of the Manager.
If this is not the same version of the add-on, a warning is shown and a
"Force Submit" button appears. This makes it both explicit that something
is iffy and still allows for pushing forward.
This is important when upgrading Flamenco, because I'm sure many people
will forget to actually redownload and reinstall the add-on.
Split the `comms.ping_manager()` function into two: one that returns the
version & config of the Manager, and the other that reports on it.
This will make it possible to do the former without the latter in certain
other situations where we want to refresh the manager info in the
background.
Whenever the URL to Flamenco Manager is updated, check it and report.
This required moving the 'ping manager' code into a separate function, as
calling an operator from an RNA update callback is not a good idea.
The add-on code was copy-pasted from other addons and used the GPL v2
license, whereas by accident the LICENSE text file had the GNU "Affero" GPL
license v3 (instead of regular GPL v3).
This is now all streamlined, and all code is licensed as "GPL v3 or later".
Furthermore, the code comments just show a SPDX License Identifier
instead of an entire license block.
