Integrate SysGus (CVC5) for synthesis of a valid subset

[alcides]

The idea is to use Program Synthesis tools that address SysGus problems (e.g., CVC5 or z3) to solve a subset of programs (no polymorphism, only native operators).

Steps to implement this approach:

• Translate Aeon Core to SysGus syntax (or fail if impossible)
• Call CVC5/z3 bindings to obtain the program
• Translate the resulting program back to Aeon.