Adds a new concept `logContext`, to be added to each log entry when in JSON format.

Closes #5551

New config option `rebaseWhen` replaces existing options `rebaseStalePrs` and `rebaseConflctedPrs`. Migration code added.

Co-authored-by: Rhys Arkins <rhys@arkins.net>
Co-authored-by: Michael Kriese <michael.kriese@visualon.de>

* linting, schema and type check should be os and node independent

* fix ensure comment

* Fix comment update mechanism

* Fix snapshots

Co-authored-by: Jamie Magee <JamieMagee@users.noreply.github.com>