* Implement SSL/TLS certificate checking #782
* SSL: Add nimDisableCertificateValidation
Remove NIM_SSL_CERT_VALIDATION env var
tests/untestable/thttpclient_ssl.nim ran successfully on Linux with libssl 1.1.1d
* SSL: update integ test to skip flapping tests
* Revert .travis.yml change
* nimDisableCertificateValidation disable imports
Prevent loading symbols that are not defined on older SSL libs
* SSL: disable verification in net.nim
..when nimDisableCertificateValidation is set
* Update changelog
* Fix peername type
* Add define check for windows
* Disable test on windows
* Add exprimental GitHub action CI for SSL
* Test nimDisableCertificateValidation
