Missing meta-data support for 360 videos

[teodoropiccinni]

I tried to import 360 video files from my insta360, OpenShot can open oit easily and I can make changhes, but when I export it all the metadata about the curve of the lens and other parameters useful for 360 video players are truncated by OpenShot.

[teodoropiccinni]

I have the local changes implemented in libopenshot. After that, a more extensive work to implement the support in the QT interface will be required.