Host an InvenioRDM Events calendar

[saragon02]

Calendar will show upcoming conferences and meetings where InvenioRDM team members plan to present and/or attend.

Utilize: https://inveniosoftware.org/events/

Update the page above with images, summary from the latest in-person Annual Partner meeting

### Tasks
- [x] create calendar
- [ ] add collaborators
- [ ] embed calendar

[saragon02]

Adding Steve Diggs to investigate including a Google calendar via iframe

[SarahW91]

As discussed at the last events & conferences interest group meeting: @saragon02 will check with CERN if a Google calendar is a good option.

[SarahW91]

Kai from Hamburg offered to set up the calendar while Markus will take care of setting everything up on the website. Thanks to both of them!

[saragon02]

Just confirming that we received the go-ahead from CERN to update the Events page. I also messaged @sdiggs about his proposal for iframes. I'll let Kai know about this issue/thread.

[Herrner]

Got it ;)
I created a calendar for events from and/or for RDM partners and plan to put one more up for events that might be of interest for partners. I'm not really sure about the second one because it's a bit difficult to filter.
I'll add members of the group as maintainers for the calendars.