Add option to turn off BIGTIFF

[banesullivan]

Adds a way to control the COG conversion utility's output and turn off the default BIGTIFF option

[manthey]

There is a IF_NEEDED value for the BIGTIFF option that we should use instead.

[manthey]

Actually, the GDAL docs say:

  -  IF_NEEDED will only create a BigTIFF if it is clearly needed (in
      the uncompressed case, and image larger than 4GB. So no effect
      when using a compression).
   -  IF_SAFER will create BigTIFF if the resulting file \*might\*
      exceed 4GB. Note: this is only a heuristics that might not always
      work depending on compression ratios.

Neither are guaranteed. Looking at the code, IF_SAFER checks if the uncompressed image is > 2GB regardless of compression. IF_NEEDED only if the uncompressed image is > 4GB AND uncompressed. So IF_SAFER will probably mostly be sufficient as the default, and then we can allow the values to be overridden as in this PR.

[manthey]

#594 is going to cause this PR to need to be refactored. It also will switch the default to IF_SAFER, which might be sufficient for most use cases.

[manthey]

I'm going to close this, as I think the changes in #594 obviated the need for it. Please reopen if you think it is still necessary.