Allow node attributes to be passed in so that guards based on attributes can be tested

[jjustice6]

We have a lot of recipes with if statements guarding recipes, in some cases the entire thing, to ensure the recipes only runs on certain machines.

This makes umami very difficult to use.

[RyanFrantz]

This would also be useful in mocking up the resulting tests (i.e. defining a set of node attributes that must be present in order for a resource to be triggered).