feat: Add PDT to each segment

[harisha-swaminathan]

Includes BREAKING CHANGES

The PR

• Adds PDT to each segment with an explicit EXT-PROGRAM-DATE-TIME tag by extrapolating backward when the first EXT-X-PROGRAM-DATE-TIME tag appears after one or more Media Segment URIs and extrapolating forward when subsequent fragments do not have explicit PDT tags

If the first EXT-X-PROGRAM-DATE-TIME tag in a Playlist appears after one or more Media Segment URIs, the client SHOULD extrapolate backward from that tag (using EXTINF durations and/or media timestamps) to associate dates with those segments.

To associate a date with any other Media Segment that does not have an EXT-X-PROGRAM-DATE-TIME tag applied to it directly, the client SHOULD extrapolate forward from the last EXT-X-PROGRAM-DATE-TIME tag appearing before that segment in the Playlist.

• Removes use of PROGRAM-DATE-TIME tag as a manifest object
• Replaces segment PROGRAM-DATE-TIME tag objects dateTimeString and dateTimeObject with programDateTime