Fix & update yuyv/uyvy encodings

[jtbandes]

User-Facing Changes

• Renamed raw image encoding uyuv to uyvy for accuracy.
• Added support for raw image encoding yuv422_yuy2 as an alias for yuyv.

Description

• Fixes Is this a mistake? there is no uyuy, does it mean uyvy? #6271, fixes FG-3953
• Schemas PR: Update RawImage encodings schemas#121

All YUV 4:2:2 formats encode one U and one V value for every two Y values. The byte orders supported by Studio and by other apps in the ecosystem are [U, Y1, V, Y2] and [Y1, U, Y2, V].

• Replaces uyuv, which seems to have been a typo introduced in Adding support for YUYV(YUV2) aside from YUV422(UYVY) along with UYVY alias #5292, with uyvy, which accurately represents the byte order we are decoding.
• Adds yuv422_yuy2 as an encoding alias for yuyv, taken from ROS:
  • sensor_msgs/image_encodings.hpp
  • Add YUYV image encoding ros2/common_interfaces#76
  • update YUV format codes and documentation ros2/common_interfaces#214
  • yuv422_yuy2 is the default encoding used by usb_cam
• Remove incorrect and useless Int8Array type casting
• Update YUV-to-RGB conversion formula to be faster and match RViz code
• Added story for both UYVY and YUYV
• Confirmed compatibility with rqt_image_view and rviz (although those two look slightly different from each other):
  

Other references:

• https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/pixfmt-packed-yuv.html

[defunctzombie]

Are we expecting any reports of folks that had recorded data with uyuv? Or is this unlikely as it is not a real format?

[jtbandes]

Seems unlikely to me. uyuv was only added as an alias to the existing (and more common) yuv422, and only 5 months ago.

[sgf201]

the YUV422P is useful, @jtbandes ,could you add the 420P and 422p support