* Move wsnext flow in Kubernetes infra implementation

Now we need to start a broker and pass meta.yaml files to it.
Starting a broker is infra-specific stuff, so it has to be done
on the infra implementation side because we don't have a part
in the infra SPI that would allow us to start a broker.
Passing Meta files using InternalEnvironment object is more
invasive than passing only attributes. So, this commit applies
less invasive scheme.

* CHE-10202,10561: Add fetching of Che editor, plugins meta from the registry

Add fetching of Che editor ID from workspace attributes.
Add fetching of Che plugins IDs from workspace attributes.
Use colon sign for separating editor/plugin ID and version
instead of the slash.
Remove old Workspace.Next model objects.

* CHE-10561: Share WS.NEXT between k8s and OS infras

Use WS.NEXT in both k8s and OS infrastructure implementations.

* CHE-10561: fix fetching meta.yaml files from che-plugin-registry

* CHE-10561: Fix sidecar model serialization

Fixes the fact that some fields in workspace sidecar tooling model
POJOs were incorrectly named or required custom serialization of
fields.

* CHE-10561: Add listening of che-plugin-broker

Add code that allows listening for events from Che plugin broker.
An event might contain workspace tooling config as a result if the broker
finished successfully or error otherwise.

* CHE-10561: Add PluginBrokerManager to control broker lifecycle

Adds PluginBrokerManager that configures/starts/waits Che plugin
broker.

Remove unused code.
Remove notion of Workspace next.

* Align plugin registry property between different components

* Fix extra  path in che plugin registry URL

Signed-off-by: Oleksandr Garagatyi <ogaragat@redhat.com>