cleanup: remove project-open stage timing logs, lower NIO-added log to debug

- Drop the diagnostic stage-timing logs added during link-create perf
  work (nodes / preallocate / prepare / dispatch) now that bottlenecks
  are resolved and verified.
- Lower the per-NIO 'added to adapter' log in docker_vm from INFO to
  DEBUG — at 5000+ NIOs per project open it floods the log at INFO.

gns3server/compute/docker/docker_vm.py

@@ -1275,7 +1275,7 @@ class DockerVM(BaseNode):
             await self._connect_nio(adapter_number, nio)
 
         adapter.add_nio(0, nio)
-        log.info(
+        log.debug(
             "Docker container '{name}' [{id}]: {nio} added to adapter {adapter_number}".format(
                 name=self.name, id=self._id, nio=nio, adapter_number=adapter_number
             )