FilterChoiceField forces queryset evaluation despite rendering only a default choice

[jeremystretch]

Environment

• Python version: 3.6.9
• NetBox version: 2.7.4

Steps to Reproduce

1. Enable debugging
2. Navigate to a device and select "Add components" > "Console port"
3. Inspect the database queries being made

(This can be replicated anywhere the APISelect widget is in use; this is just one concise example.)

Expected Behavior

Because the APISelect widget populates only a single initial choice (if one exists) and not every available option, it should not be querying the database for all options.

Observed Behavior

A query is made for all field options, even though they are unnecessary to render the widget.

[hSaria]

I think with this change, it should be okay to remove the custom template

netbox/netbox/utilities/forms.py

Lines 263 to 264 in 885ea8a

	# Only preload the selected option(s); new options are dynamically displayed and added via the API
	template_name = 'widgets/select_api.html'