Add result email task

[threexc]

The meta-python-build-patches, meta-python-build-ptest-container, and meta-python-run-ptest tasks currently only present output in their pipeline/task/step logs (CLI or via the Tekton Dashboard). There should be a step/task that sends an email to a user-customizable recipient (e.g. personal email or the openembedded-devel mailing list) available to call after each of these tasks as desired.