* Consolidate certificate supplier module
Both the proxy and the proxy needs certificate suppliers. The PR
consolidates the module that providings those bindings to a shared
module and switched the proxy to use that module. The prober currently
uses P12 file to store its certificates. I am debating keeping that
supplier ro converting them to PEM files for simplicity.
* Rename mode enum values to be more descriptive
* Update annotation names to be more descriptive
