[FW][IMP] runbot: add metadata to log_db

[fw-bot]

When handling errors on runbot, it can be difficult to know where a message comes from. It can be problematic to identify automatically the source of an error.

This branch give the possibility to add metadata to log_db.

The current only metadata is the canonical tag.

Some other information, like the stack, or the subtest could be added in the future. This is not the case for now to make the review easier.

     def get_log_metadata(self):
+        stack = traceback.format_stack()
+        start = next((index for index, frame in enumerate(stack) if self._testMethodName in frame), 0)
         metadata = {
             'canonical_tag': self.canonical_tag,
+            'stack': '\n'.join(traceback.format_stack()[start:-7]),
+            'subtest': str(self._subtest),
         }
         return metadata

Forward-Port-Of: #199964

[robodoo]

[fw-bot]

This PR targets saas-18.1 and is part of the forward-port chain. Further PRs will be created up to master.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[fw-bot]

@Xavier-Do the next pull request (#200476) is in conflict. You can merge the chain up to here by saying

@robodoo r+

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[Xavier-Do]

@robodoo r+