Update Meetings page to include future meetings

[bettina-gier]

Updated Meetings Page into "Events" and includes information on Monthly Meetings and Workshops, both past and future. Events are now tracked with a yml list and the page itself just parses the list to automatically check on compilation if the given date is past or present. This will help if we want to reference some in other pages as well.

Tutorials not included yet.

Closes #97

Link to documentation:

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[bettina-gier]

This is now ready for review! @axel-lauer @lukruh