OpenSplat support for Fisheye camera types

[RBilsland]

I've been playing with raw footage out of the Insta360 X5 camera accessing its raw fisheye video streams. I've successfully got ColMap to align, rig and the sparse render the footage but being on a Mac mini my options to render are very limited. Could OpenSplat be enhanced to support the fisheye camera types (I'm using the OpenCVFisheye camera type) that ColMap support so that I can render locally.

Thanks,

Bob Bilsland.

[pierotofy]

I'd welcome a pull request to add support for other camera types. Thanks!