Add support for H265/HEVC in FFMPEG

[Cardy2]

OSH H265 video data doesn't contain the needed parameter sets (VPS/SPS/PPS extracted from Hvcc extradata) to decode H265 video in the viewer or any downstream client.

PR adds a method to get the HVCC annexB extradata so that it is included downstream

Testing:

• add an FFMPEG sensor to a node and connect to a video stream offering H265 video
  Eg - Office Cam
  rtsp://osh:oshtest1234@cameras.simple-url.com:554/axis-media/media.amp?videocodec=h265

• Ensure that the sensor connects and is collecting data by checking the API or, minimally, ensuring the timestamp is updating

Test the video plays successfully using one of the paths below:

Transcoder Path

• Since the osh-viewer updates for handling H265 had not yet been merged, the video transcoder can be used to convert the format to a viewable codec
• Add the video transcoder under the processing tab, add the ffmpeg sensor as the "Video Source" and set the input/output codecs (H265 OR HEVC -> MJPEG OR H264) so that the video is playable in the viewer

Direct osh-viewer path

• Optionally, in order to test the H265 handling directly with the viewer, clone the botts:osh-viewer project & check out this branch:
  https://github.com/Botts-Innovative-Research/osh-viewer/tree/add-hevc-support

• after checkout, do an npm install then npm run dev

• in the viewer with dev tools open, add the node, then a video visualization with the ffmpeg driver

• check the console for any errors