Envoy should use system certificates file to validate server certificates

Author: @franek1709

Currently envoy uses certificates file from path `/etc/ssl/certs/ca-certificates.crt` to validate server certificates during SSL request. It would be better to use file based on default cert file on operating system envoy works.

AC:

Envoy sends in metadata to envoy control path of cert file for operating systems
Envoy control use this path to validate ssl certificates of upstream clusters