Extract Pelican Schedules from API so they can be archived

[gtfierro]

We should use RRULE to store the calendar settings (using a library like https://github.com/teambition/rrule-go).

For now lets pull the schedules out and publish them on a new BOSSWAVE topic (maybe the signal side of a new i.xbos.schedule interface?)

[john-b-yang]

@gtfierro @jhkolb I've completed the initial implementation of this task and I think it's at a stage where it's ready for review. I've made a pull request and referenced this issue in the request message.

[john-b-yang]

For reference, the pull request is #38