Make XDM changes for all Alpha temporary fields

[lidiaist]

What are the schemas that are affected by the issue

• media.schema.json
• time-series.schema.json
• rating.schema.json

What are examples of products that are impacted by the issue

• Adobe Media Analytics Internal JIRA issues: https://jira.corp.adobe.com/browse/VA-4673 + https://jira.corp.adobe.com/browse/VA-4663 + https://jira.corp.adobe.com/browse/VA-4661 + https://jira.corp.adobe.com/browse/VA-4999

High-level changes:

• support for playhead parameter https://experienceleague.adobe.com/docs/media-analytics/using/media-collection-api/mc-api-ref/mc-api-sessions-req.html?lang=en
• support for media types for eventType enum in time-series schema
• correct the regex of /media/mediaTimed/primaryAssetViewDetails/videoSegment to ^[[0-9]+-[0-9]+]$
• make RatingSourceLink optional since we don't ask it as input from our clients
• integrate multiple player state tracking for ee integration by adding statesStart and statesEnd