(Maint) Add memory terminii for CR and Key

These are sometimes useful in tests when we don't want to deal with
saving the certificates to disk, but will want to allow them to be saved
somewhere.
(#23116) Provide pluggable SSL verification

This provides the ability to create a verifier for SSL connections
opened with puppet's Puppet::Network::HTTP::Connection. The verifier is
provided the Net::HTTP connection and it just needs to configure it for
the correct verification mode.

The new functionality can be used when puppet's standard SSL
verification rules are not suited to the needs of the caller. The
impetus for this was a requirement that a connection be able to be made,
the certificates checked, but the subject and alt name checks skipped.
Rather than put that directly into puppet, this allows a new validator
to be written that performs those checks.
(#23116) Make SSL Validator API more explicit

This refactors the API with an abstract superclass that contains
the API documentation and two factory methods; to obtain the no
validation implementation, and the default implementation.

Yardoc reworked.
Merge pull request #2093 from hlindberg/feature/issue-23116-allow_certificate_verification_post_factum

(#23116) Provide pluggable SSL verification
(Maint) Remove unstable and not useful test

This entire test often failed, or hung, because of networking problems.
We get coverage for what it is doing either through unit tests or
through full-system tests that run the webrick server.