Flag invalid contract name on `check`, `test`, `deploy`

[lgalabru]

Clarinet accepts invalid contract names, which result in surprises when these same contracts are being published on chain.

[obycode]

@lgalabru Is this a duplicate of #233?

[lgalabru]

Kind of yes. #233 is requesting check at contract creation, but we probably want to run these checks everytime we're loading the contracts (checks, tests, deploy, etc).