Log Message:
z3 py-z3: updated to 4.12.5

z3-4.12.5

update release scripts and notes
track quantifier instantiation method in proof hint
prepare for release
add status badge for windows build, remove windows build from Azure pipelines
add Windows build
free memory the clean way
free memory the clean way
encapsulate anum functionality
add explicit move constructor to deal with unit test regression test-z3 \ 
algebraic on Windows/debug -
encapsulate mpz a bit more