Add high performance, correct font compiler requirements document

Add a Markdown document that outlines what the requirements for a high performance, correct compiler are, why, and what the impact of having or not having a fast compiler are as a starting point.

Address the following in the document:

- ~~does it need to be developed in Rust?~~
- does it need to be developed as a new compiler from scratch, rather than an incremental transition of the existing Py compiler pipeline? If incremental vs from scratch is believed to be key this should be explicit in the document
- speak to how much impact for how much faster. Whats the smallest speedup that has value and when does the value of speedup diminish in value? - for example, perhaps a 10% speedup doesn't help much, 2x would be very nice, 10x might be about where the value peaks (then we dont' take a coffee break every compile), and maybe 100x is sort of nice but doesnt' matter, 10x was good enough.
- when do we need it?