Remove sygus1 parser (#4651)

Remove sygus1 parser (#4651)

We no longer support sygus v1 inputs. This PR removes support for sygus v1 (as well as a deprecated "z3str" variant of smt lib 2 which is subsumed by the new strings standard).

As mentioned in the release notes, CVC4 1.8 supports a conversion from sygus v1 to v2 script.

This removal is required for further updates to the new API. Further infrastructure (e.g. the sygus print callback) will be removed in a separate PR.

FYI @abdoo8080 .