Proposal to add support for RFC 7714 SRTP with AES-GCM

[jcbeaulieu]

Proposal for cryptographic algorithm negotiation to add support for RFC 7714 SRTP AES-GCM.

Reason: EU governments will start forbidding SHA-1 starting 2025 December 31. RFC 3711 defines an 80 bit SHA-1 authentication tag, which will be forbidden. Using AES-CM (Counter Mode) without an authentication tag is insecure and forbidden by FIPS.

Compatibility analysis: Devices that do not support the feature will not include the SecureRTSPStreamingAlgorithms in the StreamingCapabilities. Clients that do not support the feature will not include the SecurityProtocolAlgorithm the GetStreamUri. When either a client or device does not support the feature, AES-128-CM-SHA1_80 is implied. (As defined in RFC 3711).