VW version requirement and documentation on config_constraints vs metric_constraints (#686)

* add vw version requirement

* vw version

* version range

* add documentation

* vw version range

* skip test on py3.10

* vw version

* rephrase

* don't install vw on py 3.10

* move import location

* remove inherit

* 3.10 in version

Co-authored-by: Chi Wang <wang.chi@microsoft.com>