Please make ProtectionProfile methods public

[sirzooro]

Summary

Please make ProtectionProfile methods public

Motivation

I am implementing SRTP support for my RTSP Server. I need to send key management parameters using MIKEY protocol to RTSP client. They include lengths of key, salt, etc.

Describe alternatives you've considered

I added constants for these values to my code. Calling ProtectionProfile methods to get these values would result in cleaner code.

[Sean-Der]

That sounds great! Mind opening a PR?