Add support for qualityRanking attribute in DASH manifests

[Janet101]

Description

This PR adds support for parsing the qualityRanking attribute from DASH MPD manifests and mapping it to the HLS SCORE attribute for video.js compatibility.

The qualityRanking attribute specifies the quality ranking of a representation relative to others in the same adaptation set. Higher values represent lower quality content. This is mapped to HLS's SCORE attribute, which serves the same purpose and allows video players to make more informed decisions about quality selection beyond just bandwidth considerations.

Example

<Representation id="high" bandwidth="2000000" qualityranking="10">
  ...
</Representation>

Output (HLS playlist attributes):

{
  NAME: 'high',
  BANDWIDTH: 2000000,
  SCORE: 1/10,
  ...
}

Test Results

All tests pass successfully:

• ✅ 196 tests passing (0 failures)
• ✅ 100% coverage on parseAttributes.js
• ✅ Overall coverage: 96.64% statements, 89.46% branches

[Janet101]

Hi @gesinger @brandonocasey @gkatsev @forbesjo , hope you’re doing well 😄! This is my first contribution to the repo, would you mind taking a look when you have some time?
I’d really appreciate your feedback!