Add script to create a snowflake rota reminder

I was playing a bit with Rundeck/MM/python/bash and decided to create this script that reads our logbook.md, get the next person in rota and the day the rota starts and executes and http post to a mattermost hook. The idea is to execute the script via rundeck (every friday) so the cloud-infrastructure channel will be aware of who is the next person in rota without the need of checking the logbook.

It would look like:

Rundeck Job: https://cci-rundeck-dev.cern.ch/project/Tests/job/show/9a65fd7e-421f-48dc-9c75-3339709e2cfc

We could also add the option to send an email to the person in rota but for that we would need to store email addresses manually... And I think it is better to have sth automatic that we don't have to modify every time someone is added/removed from the rota.