[Feature] Add blanket tarrif/subsidy capability

[gonuke]

What is the motivation for your feature request? Please describe what you want to use it for.

The TariffRegion (#661) allows tariffs/subsidies to be applied to a list of other named regions. It may be useful to apply tariffs/subsidies uniformly to all other regions that are not named in the list.

Describe the feature you'd like.

Add a new input as a blanket tariff/subsidy rate and check it to apply when appropriate.

Describe alternatives you've considered.

Explicitly list every other region and define a tariff/subsidy, but this is fragile to missing one in the list.

[dean-krueger]

Removing from Krueger Research Plan since it's being addressed in Tariff Region PR

[gonuke]

(Not that you need to reverse this, but it could stay in the research plan even if it's being resolved by the TariffRegion PR??)

[dean-krueger]

I put it back :)