Do not start nodes when deleting a project

Project.delete() calls open() to rebuild the internal data structures
needed for cleanup. open() schedules start_all() when the project has
auto_start enabled, so deleting an auto-start project actually launched
every node process, allocating ports and consuming resources, only for
close() to kill them moments later.

open() now takes an auto_start argument (default True, so normal opens
are unchanged) and delete() passes auto_start=False.

Fixes #2784

tests/controller/test_project.py

@@ -655,6 +655,19 @@ async def test_delete(project):
     assert not os.path.exists(project.path)
 
 
+async def test_delete_does_not_start_nodes(project):
+    """
+    Deleting a project must not start its nodes, even when auto_start is enabled.
+    """
+
+    project.auto_start = True
+    project.dump()
+    await project.close()
+    project.start_all = AsyncioMagicMock()
+    await project.delete()
+    assert not project.start_all.called
+
+
 async def test_dump(projects_dir):
 
     directory = projects_dir