Suggestion: Link BetterVent to csh-calendar2

[dax-dot-gay]

Basically: Add a 2-way link between BetterVent and CSH-Calendar2 so that events added on CSH-Calendar2 can be sent to BetterVent and vice versa.

Required Features:

• CCal2 must add a POST endpoint for adding new events that are not linked to google calendar, perhaps adding these events to the google calendar if necessary.
• BetterVent must then implement a connection to this endpoint and the rest of the CCal2 API to get events with the BetterVent tag and add them to the calendar. This part can theoretically be done now with a CCal2 config tweak to add BetterVent tags.