Provide a simple runner which runs from a folder of images

[ayushbaid]

We have runners for specific datasets, but there is no simple way right now to just run GTSFM on a folder of images.

We can solve this using the following:

1. Reintroduce depricated FolderLoader or some version of it which just takes in a folder of input images.
2. Infer intrinsics from the exif file and the sensor database. If intrinsics cannot be inferred, approximate it from the image shape.
3. Perform fundamental matrix estimation instead of essential matrix estimation.

Additional benchmarks needed for this task:

1. F-matrix estimation for a few datasets.

[ayushbaid]

@johnwlambert please add/modify information as you find useful.

[johnwlambert]

Hi @ayushbaid, I was able to run the Olsson runner today with EXIF only. Other libraries like OpenMVG also require EXIF, so I think it's a reasonable assumption for now.

[Padarn]

@johnwlambert you are right, we do not have EXIF (at least not in the standard format, we have it in other metadata. I can implement my own loader to read the EXIF in a different way.

Thanks a lot!