[Core][Autoscaler] Refactor v2 Log Formatting (ray-project#49350)

Currently the V2 Autoscaler formats logs by converting the V2 data
structure `ClusterStatus` to the V1 structures `AutoscalerSummary` and
`LoadMetricsSummary` and then passing them to the legacy
`format_info_string`. It'd be useful for the V2 autoscaler to directly
format `ClusterStatus` to the correct output log format. This PR
refactors `utils.py` to directly format `ClusterStatus`. Additionally,
this PR changes the node reports to output `instance_id` rather than
`ip_address`, since the latter is not necessarily unique for failed
nodes.

## Related issue number

Closes ray-project#37856

---------

Signed-off-by: ryanaoleary <[email protected]>
Signed-off-by: Ryan O'Leary <[email protected]>

Author: ryanaoleary

python/ray/autoscaler/v2/tests/test_utils.py

@@ -555,10 +555,10 @@ def test_cluster_status_formatter():
 Pending:
  worker_node, 1 launching
  worker_node_gpu, 1 launching
- 127.0.0.3: worker_node, starting ray
+ instance4: worker_node, starting ray
 Recent failures:
  worker_node: LaunchFailed (latest_attempt: 02:46:40) - Insufficient capacity
- worker_node: NodeTerminated (ip: 127.0.0.5)
+ worker_node: NodeTerminated (instance_id: instance5)
 
 Resources
 --------------------------------------------------------
@@ -573,18 +573,18 @@ def test_cluster_status_formatter():
  {'GPU': 2} * 1 (STRICT_PACK): 2+ pending placement groups
  {'GPU': 2, 'CPU': 100}: 2+ from request_resources()
 
-Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00001
+Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00001 (head_node)
  Usage:
   0.5/1.0 CPU
   0.0/2.0 GPU
   5.42KiB/10.04KiB object_store_memory
 
-Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00002
+Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00002 (worker_node)
  Usage:
   0/1.0 CPU
   0/2.0 GPU
 
-Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00003
+Node: fffffffffffffffffffffffffffffffffffffffffffffffffff00003 (worker_node)
  Usage:
   0.0/1.0 CPU"""
     assert actual == expected