ALLOWED-CPC Support

[robwalch]

Is your feature request related to a problem? Please describe.

Enhance support for level filtering with key selection and ALLOWED-CPC attribute

Describe the solution you'd like

• Add parsed ALLOWED-CPC information to Level or LevelDetails
  • (CPC labels will differ for each KEYFORMAT: ALLOWED-CPC="${KEYFORMAT}:${fwd-slash-delimited-CPC-labels}"
• Use ALLOWED-CPC along with key system access and HDCP security level to filter and select levels for playback
  • Ex: Add new API event when key-system access is gained (externally, the API only offers license callbacks), and use it to filter levels with ALLOWED-CPC values that do not include the key-system KEYFORMAT

Additional context

See ALLOWED-CPC under https://datatracker.ietf.org/doc/html/draft-pantos-hls-rfc8216bis#section-4.4.6.2