Extract function preventFormSubmission and move it to form-utils
Publish the set of filter names in "predictive-filters-root"

The object is intended to be completed as a full predictive filters
structure by iterating over each author in filter-authors.
Complete predictive filters structure while iterating authors
Add missing constant CATEGORY_NAME in filter-constants
Remove extra space characters before commas
Move reference to filter-constants to HTML header with utils
Remove unused constant from prepare-predictive-filters

The constant was actually missing in a different module: filter-authors.
Add missing constant CATEGORY_NAME in filter-authors
Move constants from filter-authors to filter-constants
Load filter-constants before filter-utils

I intend to use constants from filter-constants in filter-utils,
which requires the former to be defined before the latter.
Fix value of constant CATEGORY_AUTHORS

The actual offset is 1, not 2.
Move constants from filter-utils to filter-constants
Use predictive filtering to display total authors selected in filters

There remains a mismatch in the filterValue used to retrieve the totals
which is a list item value in storage and a list item name in query,
leading to totals of zero returned for all filters.
Fix mismatch in filterName/filterValue

I added an extra parameter filterValue.