Implement maxHdcpLevel HDCP-LEVEL capping and EME error handling

[robwalch]

This PR will...

• Implement hls.maxHdcpLevel getter/setter API for HDCP-LEVEL capping and EME error handling.
• Sort levels primarily by HDCP level, followed by bitrate (AVERAGE-BANDWIDTH or BANDWIDTH - this is the current behavior), followed by SCORE, followed by RESOLUTION (height).

Why is this Pull Request needed?

Allows for playback of DRM protected streams with HDCP restriction to recover from output-restricted EME Key errors (ErrorDetails.KEY_SYSTEM_STATUS_OUTPUT_RESTRICTED).

Are there any points in the code the reviewer needs to double check?

1. Setting hls.maxHdcpLevel does not prevent levels from being manually selected by setting one of the manual level selection setters. Use hls.removeLevel() to remove all levels of a particular HDCP-LEVEL as selection options.
2. Setting hls.maxHdcpLevel does not immediately force a level change. To do do, set hls.currentLevel to -1 after setting hls.maxHdcpLevel.
3. Levels will not be sorted in bitrate order when variants with lower HDCP-LEVELs have higher BANDWIDTH values than their counterparts with higher HDCP-LEVELs. As this will typically only the be the case with variants containing different codecs it should not present a problem bitrate adaptation which is currently restricted to the renditions using the compatible codecs.

Resolves issues:

• Resolves HDCP-LEVEL capping and EME error handling #4923
• Closes hls js always picking worst level on auto level mode #4966

Checklist

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• API or design changes are documented in API.md