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/controller/node.py

@@ -30,6 +30,7 @@ from .controller_error import (
 from .node_types import BUILTIN_NODE_TYPES
 from .ports.port_factory import PortFactory, StandardPortFactory, DynamipsPortFactory
 from ..utils.images import images_directories
+from ..utils.application_id import is_iol_runner_environment
 from ..utils import macaddress_to_int, int_to_macaddress
 from ..config import Config
 
@@ -804,7 +805,7 @@ class Node:
             self._ports = DynamipsPortFactory(self._properties)
             return
         elif self._node_type == "docker":
-            if "GNS3_IOL_RUNNER=" in (self._properties.get("environment") or ""):
+            if is_iol_runner_environment(self._properties.get("environment")):
                 # IOL adapters are 4-port units (the IOU model): ports are
                 # Ethernet0/0-3, Ethernet1/0-3, … addressed as
                 # (adapter_number, port_number 0-3).