Step 2: Use the preferences for a cycamore reactor to change recipies

[nsryan2]

This PR closes #4 by creating a cycamore reactor single-deployment scenario that uses preferences to switch from one recipe of fuel to another.

Notes about this method:

1. there is a period where the two fuels overlap in the reactor if you do not make the number of assemblies removed the size of the reactor
2. I am unsure if this would work for multiple changes (so it's very granular). I have created a new issue (Test multiple preference changes for cycamore #5) corresponding to testing this idea.
3. This PR does not make use of <recipe_change_times> (I wasn't able to get them to work, more effort would be required to debug that implementation on my end)