[analyzer] Templatefy SMTConstraintManager so more generic code can be moved...

[analyzer] Templatefy SMTConstraintManager so more generic code can be moved from solver specific implementations. NFC.

Summary:
By making SMTConstraintManager a template and passing the SMT constraint type and expr, we can further move code from the Z3ConstraintManager class to the generic SMT constraint Manager.

Now, each SMT specific constraint manager only needs to implement the method `bool canReasonAbout(SVal X) const`.

Reviewers: NoQ, george.karpenkov

Reviewed By: george.karpenkov

Subscribers: mgorny, xazax.hun, szepet, a.sidorin, Szelethus

Differential Revision: https://reviews.llvm.org/D50770

llvm-svn: 340533