Serialize FormulaStructs in the internal API

[Rylan12]

This is a cleaner attempt of #21429.

I've added serialize and deserialize methods to FormulaStruct to efficiently store formula data in JSON format. After the simplifications made in #21455, the code needed to accomplish this is pretty straightforward.

The goal is that the only special handling needed in FormulaStruct#serialize and FormulaStruct#deserialize is for cases where there is a simpler way to store the data than is needed by Formulary. At the moment, the only two customizations needed are:

• bottle data: only need to store the relevant checksum (and can leave information like the bottle tag, cellar, and rebuild if they are the default values)
• dependency/uses_from_macos information: deduplicate dependencies that are both stable and head deps by storing shared dependencies separately

I also added a handful of methods to Utils so they can, eventually, be used by CaskStruct. I've added tests for all of these methods.

[MikeMcQuaid]

Thanks! Good to merge when comments addressed.