feat: allocate IOL Docker application IDs from a pool disjoint from IOU

IOL interface MACs derive from the application ID (aabb.cc{app}{iface}),
so ids must be unique across opened projects sharing computes — the same
reason IOU has its allocator. IOL Docker nodes draw from the upper half
(512-1022, netiomux's fixed peer is 1023) so the two node types can
neither collide nor starve each other; IOU behavior is unchanged.

The controller sniffs the same GNS3_IOL_RUNNER environment marker the
compute uses to select IOLDockerVM (both the nested-properties and
template/top-level-kwarg shapes), stores the id in node properties like
IOU does, and passes it through the Docker create payload. Without an
allocation the compute falls back to a stable node-derived id in the
same upper range.

gns3server/schemas/compute/docker_nodes.py

@@ -69,7 +69,9 @@ class DockerCreate(DockerBase):
     Properties to create a Docker node.
     """
 
-    pass
+    application_id: Optional[int] = Field(
+        None, ge=1, le=1022, description="IOL application ID for iol-runner images (allocated by the controller)"
+    )
 
 
 class DockerUpdate(DockerBase):