Miscellanous tasks

[jaisnan]

• Parallelize test queue
• Check for race conditions among proofs
• Ensure that the proof runner is in the right directory (i.e use the full path for kani binaries)
• Add configurations for the way users want to run their proof and detect new harnesses (automatic vs reload)
• Add more kani command line options to be used optionally by the user
• Improve source parsing (i.e Handle cases where rust files dont have proofs)
• Refactor code to be more modular
• Give constraints to optional inputs
• Move to an API model (structured responses from Kani)