Provide search filter option for badge template list

[dnsturrock]

When selecting a badge template to be associated with a Moodle course, the display is a simple drop-list. When the number of badge templates to choose from gets large, this method will be very clumsy.

Suggest adding a search/filter option to reduce list length based on collections and/or template name.

[yancyribbens]

@dnsturrock thanks! I've tagged this as a future enhancement.

[zioth]

For future reference to the implementor: You can use this form control:
https://docs.moodle.org/dev/lib/formslib.php_Form_Definition#autocomplete
with the parameter I'm about to add to search_badges