rfc: API for stabilizer rank decomposer

[rafaelha]

The current decomposition techniques in tsim are very basic (only BSS and some version of cat decomposition for general rotations are used).

I would be good to support more elaborate decomposition strategies.

• cat decomposition
• star decomposition
• cutting decomposition
• making use of connected components that arise during a decomposition (this would require changes to the compilation part of tsim)

Some useful resources

• quizx's decomposer
• J Codsi's thesis
• https://github.com/Codsilla/ZX-stabiliser-simulator

The purpose of this issue is to converge on some API/design for a decomposer