fix(yer): set max length of file fields to 255

 #668
feat(yer): handle user_override in YER view

get from url params, pass into template

 #669
feat(yer): add staff override to YER links on home page

 #669
feat(yer): initialize yer form js with user_override, display in header

 #669
refactor(grants): add docs to registered_org decorator