Add mediasource type, support SMTC for windows and android

[JieNiGui06]

• Feature/Proposal

Description of Change

I'm aiming to make the mediaelement to adapt to all the platform, but now, I only tried it on windows.

1. Add the MediaSource-type:
   MetaMediaSource. Include Metadata, http-headers in source.
   HttpMediaSource. Include sets of MetaMediaSource, default-http-headers, startindex.

2. Results:
   I can set a list of Playbackitem to the Mediaelement and auto to refresh the metadata for each playbackitem.

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description) only on windows and android
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

[JieNiGui06]

@dotnet-policy-service agree

[JieNiGui06]

I can only do it on windows and android.
On mac or ios, I don't know how to do.