Autocompleters: CSS and helper refactor

[nimmolo]

• Alter autocompleters to use Bootstrap "dropdown" CSS classes where possible. (Requires changing autocompleter item markup from simple <li>Option</li> to <li><a href="#">Option</a></li>, but we get hover and click events for free, and easier BS upgrades.)
• Change the arg for "autocompleter query type" in autocompleter_field helper from autocomplete: to type:.
• Stimulus housekeeping: Change the root element of an autocompleter controller from the input (whose sibling is the .auto_complete list) to the parent element for both.
• Better functionality for swapping the autocompleter type (to be used for new "locations_containing" lat/lng)
• New working "Region" autocompleter, for "Help Identify"

There should be nearly no change in appearance or function, otherwise.

[coveralls]

coverage: 94.45%. remained the same
when pulling ef1d797 on autocompleters-refactor-js
into bc2ed6f on main.

[coveralls]

coverage: 94.45%. remained the same
when pulling 8d567a1 on autocompleters-refactor-js
into bc2ed6f on main.

[coveralls]

coverage: 94.45%. remained the same
when pulling ce73d93 on autocompleters-refactor-js
into bc2ed6f on main.

[coveralls]

coverage: 94.407% (-0.04%) from 94.45%
when pulling c709ed9 on autocompleters-refactor-js
into bc2ed6f on main.