stats tables view with dummy data impl.
use actual form endpoint
Added languages to view
mo need to re-render select when the question changes
button states based on validity
populate view model on create
retrieve stats from api
only show stats view if mean, mode or median is enabled
added frequency data
reset summary methods whenever a new field is selected
only show freq. table if freq. or percentage is enabled
select option languages and various fixes [ci skip]
LW: merge with master
moved files to viewer app
test tables view response code and fix odk_viewer url
Exposed StatsSummariesEnabled util function
LW: Moved builder construction to template as it relies on template vars for urls
LW: Initial js tests for stats tables UI
LW: Test stats parsing
LW: Test button disable functionality