[IMP] conf: vendor python inventories

Reaching external ressources while running tests is an important source
of random error and can even causes deterministic errors when a service
is down for a while.

Runbot will soon block all external requests, this commit follows
changes introduced in #13669 and vendors the python inventories.

closes #13754

X-original-commit: 5a69ad5
Signed-off-by: Xavier Dollé (xdo) <[email protected]>

Author: Xavier-Do

conf.py

@@ -212,7 +212,7 @@
 todo_include_todos = False
 
 intersphinx_mapping = {
-    'python': ('https://docs.python.org/3/', None),
+    'python': ('https://docs.python.org/3/', '../invs/python.inv'),
     # apparently local inventories are relative to the source dir?
     'werkzeug': ('https://werkzeug.palletsprojects.com/', '../invs/werkzeug.inv'),
 }