Replace custom Dropdown component with Bootstrap dropdowns and regular <select>s where relevant

[eatonphil]

[eatonphil]

I'm going to suggest we move to Bootstrap dropdowns and regular selects everywhere instead of the custom dropdown component.

[eatonphil]

So I'm going to punt on this and pull this out of "in progress" for now. I'll add another task to actually customizing the dropdowns and selects after the switch to bootstrap.

[ddevault]

👍