* core no longer exposes create_remote/local_object
* node, device & link have constructor methods
  to enable the create_remote_object functionality
* added WpImplNode to wrap pw_impl_node and allow creating
  "local" node instances
* added WpSpaDevice to wrap spa_device and allow creating
  "local" device instances
* exporting objects in all cases now happens by requesting
  FEATURE_BOUND from the proxy, eliminating the need for WpExported
* replaced WpMonitor by new, simpler code directly in module-monitor
* the proxy type lookup table in WpProxy is gone, we now
  use a field on the class structure of every WpProxy subclass
  and iterate through all the class structures instead; this is
  more flexible and extensible

+ use the pw_proxy API to find the bound id instead
of relying on WpGlobal

This has the advantage that it works also for exported
objects and for objects that have been created by calling
into a remote factory (such as the link-factory), so we can
now know the global id of all proxies, not only the ones
that have been created by the registry.

They are equivalent, there is no real benefit in having both

This module allows wireplumber to create static nodes that match a specific
device using a spa node factory. Matching is optional, and if there is no match,
the node will always be created.

This ensures that endpoints with keep=false will still have
a chance to link when ones with keep=true exist. This also effectively
means that role priority does not matter when keep=true: we keep these
links active no matter what, while policy still applies normally for
all others.

For example, a final sorted list with these endpoints will end up
looking like this:

* ep1, role priority=25, keep=false
* ep2, role priority=20, keep=false
* ep3, role priority=25, keep=true
* ep4, role priority=75, keep=true

... which will effectively cause ep1, ep3 and ep4 to be linked.

keep=true should work in both ways:
* keep the endpoint with this property linked at all times
* keep other already linked endpoints when linking this one

This is no longer needed since we sort endpoints by role priority
before trying to link them and we link only the highest priority one.
After this sorting, the highest priority endpoint is guaranteed
to be able to link, so _can_link_stream() always returns TRUE.

This is now done by the config endpoint module

and drop the WpBaseEndpoint controls entirely

This keeps track of the default endpoint and selects a default
based on endpoint priorities when devices are discovered

Clear self->pending_endpoint before sending the done signal,
because the signal will trigger a new endpoint to be added in the
unit test and this may happen before g_clear_object is called,
in which case adding the new endpoint fails

to avoid name clashing with the upcoming WpEndpoint interface
that is going to be the common interface of Wp{Proxy,Exported}Endpoint

This avoids hearing mono audio only on the left speaker