Select problem by type

Internal/temporary PR for review.
These names should match the names used in Studio... I just tried to find "Numerical Response" and it wasn't on this list - eventually I realized that it's called "Formula Equation" here. I think you should change all these to be the same as in the "Add Component" menu. You might also want to change them to look at the response type tag rather than the input type tag?? (Not sure which is "better")

e.g. Below the response type is `numericalresponse` and the input type is `formulaequation`

```xml
<problem>
<p>Calculate the total kinetic energy released in the β decay of a single free electron.</p>

<p>Enter K in MeV:</p>
<numericalresponse answer="0.783">
  <responseparam type="tolerance" default=".001" />
  <formulaequationinput label="Enter K in MeV:" />
</numericalresponse>

</problem>
```