[SMTChecker] Rename SMTChecker to SolCMC (Solidity compiler model checker)

[blishko]

The module known as SMTChecker has evolved from a simple BMC-like approach to a proper model checker. It would be good to reflect the current status in the module's name.
Moreover, a paper about the module has already been published where the new name, SolCMC has already been used.
A new breaking release is a good time to update the name.