[handshake-sim] Added JSON configuration for execution model

[Polymeth]

Added JSON configuration file to select execution models
Added --change-model command to modify execution models configuration and JSON

[lucas-rami]

Looks pretty good but some things to address. I actually had no idea that LLVM had JSON parsing support, this is great. Aside from what I wrote please use clang-format/clang-tidy on the code. I opened handshake-simulator.cpp in my IDE and there are some code warnings + formatting issues.

[lucas-rami]

Couple of very cosmetic things to change, but all good otherwise, thanks!

One important thing though, the PR includes a CIRCT change that should not be there (you can see it on the "Files changed" tab of the PR). To fix pull all changes (including from submodules), cd to the circt folder, checkout the HEAD of main there, go back to the top-level dynamatic folder, and git add circt (then commit and push). It should fix the issue.

[lucas-rami]

I went to fix the CIRCT commit myself, it was kinda a mess but hey, it works.