The basic APIs for the CRL Reloading features.
This adds external types to represent CRL Providers, CRLs, and
CertificateInfo.
Internally we will use `CrlImpl` - this layer is needed to hide OpenSSL
details from the user.
GRFC - https://github.com/grpc/proposal/pull/382
Things Done
* Add external API for `CrlProvider`, `Crl`, `CertInfo` (`CertInfo` is
used during CRL lookup rather than passing the entire certificate).
* Add code paths in `ssl_transport_security` to utilize CRL providers
* Add `StaticCrlProvider`
* Refactor `crl_ssl_transport_security_test.cc` so it is more extensible
and can be used with providers
added the verified root cert subject to the lower level
`tsi_peer`. This PR is a companion to that and completes the feature by
bubbling the information up to the `TsiCustomVerificationCheckRequest`
which is part of the user facing API for implementing custom
verification callbacks.
* Tooling to remove redundant grpc_core:: namespaces
These references tend to show up in our C++ code after C modules get
converted. Many get caught in review, many get missed.
* use it
* clang-format