Inline meetings into the section table

[A1Liu]

Meetings aren't shared by different sections, and having a separate table makes querying the DB quite a bit more complicated. Might as well simply inline the data into a jsonb

[A1Liu]

This would speed up certain queries but may harm other use-cases, like querying for which class is happening in a specific classroom at a specific time (something we probably will never need but seemed very cool yesterday)