Real-time trajectory visualization

[Ryohei Sasaki]

The viewpoint of the real-time trajectory visualization is fixed, but it would be better to change it as the trajectory transitions.
This can be achieved with the following

https://github.com/MapIV/eagleye/tree/main-ros2/eagleye_util/fix2kml

<LookAt>
  <longitude>-122.0849</longitude>
  <latitude>37.4223</latitude>
  <altitude>50</altitude>
  <heading>0</heading>
  <tilt>45</tilt>
  <range>500</range>
  <altitudeMode>relativeToGround</altitudeMode>
</LookAt>

Also, this package does not have readme.md, which would be nice to have.

draft

This package can be visualized using [the app version of Google Eartrh](https://www.google.co.jp/earth/about/versions/#download-pro) by opening networklink.kml.
networklink.kml reads the kml file specified by href at refreshInterval [sec] intervals and visualizes it in real time.
      <href>eagleye_fix.kml</href>.
      <refreshMode>onInterval</refreshMode>.
      <refreshInterval>0.02</refreshInterval>
https://github.com/MapIV/eagleye/blob/main-ros2/eagleye_util/fix2kml/kml/networklink.kml#L26-L28 (