The `id` is defined to be sent only once, on creation of the handle or
later. And only for workspaces that are "likely to be stable across
multiple sessions".
Set we add an `id` initially for pinned workspaces, and add one when the
workspace is pinned.
The `id` is not supposed to be human readable, so we just use a random
value.
Adds support for cosmic-workspace-v2 pin, unpin, move_after, and
move_before requests.
Both features need some work with workspaces span displays mode, so that
will need more fixes later.
We also want to generate a unique id for pinned workspaces to send in
the ext-workspace-v1 protocol. But that isn't a strict requirement for
anything. So I haven't yet fully implemented that. We'll also want to
persist other things, like workspace naming when that's added.
Overall, though, with separate workspaces per display, this is working
pretty well.
This is slightly simpler, if there's not some reason I'm missing to do
this as it was previously done. And in particular provides a cleaner
API (if we wanted to move this to Smithay; perhaps without the Cosmic
extension).
But it also should be more correct. Presumably if a client (unusually)
had multiple components with their own `ext_workspace_manager_v1`
instance, they should have their own queues, and
`ext_workspace_manager_v1::commit` should be independent.
Inevitably, there's a racy element to multiple components trying to
update the workspace state like this, but it should behave the same as
two clients with separate connections.
(This is different from `CompositorClientState`, since the commit queue
there is fundamentally tied to the client, and different components with
their own compositor instance way have related surfaces.)
This new protocol extends `ext-workspace-v1` with the same additional
functionality `cosmic-workspace-v1` provided. Toplevel info and toplevel
management are also updated to use ext handles, and there's an image
source for ext workspaces.
For now, the old protocol is still supported.
