ISSUE#454. Create separate controller for files rather than reuse
controller for overview and have methods called multiple times.
ISSUE#453. Add templates conversion and users table
conversion (preferences/templates). Fix issue with populating the
denorms. Fix bug where is_checked wasn't returning false if it didn't
find anything.
Merge branch 'current-sprint' of github.com:prisms-center/materialscommons.org into current-sprint