More root cause info in the exception when CA cert verification fails

[andy-maier]

The new requests-based implementation (and also the earlier implementation) is quite brief when the CA certificate verification fails:

ConnectionError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:727); OpenSSL version used: OpenSSL 1.1.1d 10 Sep 2019

This issue is to find out whether and how it is possible to include some more information about what was wrong. Even showing the CA certificate file/directory would help, but showing which part of the verification failed would be even better.

[andy-maier]

This one should be started by reporting the exceptions that are raised when CA verification fails, e.g. with a number of common cases.

@KSchopmeyer has agreed to do that and post the results. Could be done in conjunction with issue #2038.

[andy-maier]

Moved to next release along with issue #2038 .

[andy-maier]

A few common cases are:

• CIM server presents a server certificate that is expired (and otherwise valid).
• CIM server presents a server certificate that has a different subject name than its hostname (and is otherwise valid).
• CIM server presents a server certificate that is valid but CIM client does not have a matching CA certificate.