Settings should be saved in the View's config, not in a database table

[laryn]

This caused me some head scratching until I realized that any settings changed in this module were being saved in a separate database table, not in the Views configuration. It seems that should be changed and the database table dropped after an upgrade path to convert those settings into config that is saved in the Views config files directly.

Does that sound right to you @stpaultim ?

[laryn]

Hmmm.. maybe relevant:

 * Because we want our views_distinct options available across all handlers, and
 * aren't a handler ourself, we need to store our field options independently.
 * All options on the config form that are NOT in
 * views_handler_field::option_definition() (ours are not) will be filtered out
 * by views_object::unpack_options() when the Views form callback is fired.

[laryn]

Regardless, it should be config!