VT: Enhancements on RTP depacketizer (2)

  - Send FIR if there was no I-frame within a sec in packetLost
  - Fixed an issue dropped frame even it is completed. caused by
      ABuffer marked as 'damaged'.
  - Provides completed I-Frame only to prevent codec stuck.
  - Change time mapping as realtime since rtp time is already covered
      by jitter buffer.
  - Removed periodic RTCP:FIR requests if video call. Cause i-frame
      insertion should happened only if video stream is broken.
  - Give default value for uninitialize TrackInfo Value because
    video stucked at the first frame all the times by Uninitialized
    trash TimeScale & NormalPlaytime values make AccessUnit's ntp time
    wrong.

Bug: 165061754
Change-Id: Ied41ea57d4fa96d4c05d7f8eba3d96bcb8f3fc69
Signed-off-by: Kim Sungyeon <sy85.kim@samsung.com>
Signed-off-by: Byeongjo Park <bjo.park@samsung.com>