Merge OSEM v7

[cycomachead]

TODOS:

• [x] Resolve linter comments

• [x] Proposal#edit needs to load markdown correctly

• [x] figure out what's going on with selectize

• [x] 'Materials' partials now say 'Update Commerical'

• Updates to Rails v7

• Refactors all forms.

• needs lots of testing

[cycomachead]

• [x] proposal#edit does not save existing speakers correctly. (Problem in upstream!)