Refactor window.formulaForm properties

[PhantomWatson]

window.formulaForm.schoolTypes and window.formulaForm.gradeLevels would be easier to work with if they were changed from arrays to maps.

[PhantomWatson]

On second thought, since some modules may want to index this data by IDs in some cases and by names in others, it may be more practical to keep using arrays in window.formulaForm and allow React modules to convert this data into maps as appropriate.