Remove cogify

[gadomski]

Related Issue(s): #216

Description: As @geospatial-jeff mentioned in #216 (comment), our cogify function is a poor re-implementation of rio-cogeo. Since we aren't adding any value in stactools, this PR just removes our cogify function. Downstream libraries that were using cogify should switch to using rio-cogeo.

This is obviously a breaking change, so should be part of a minor release.

PR checklist:

• Code is formatted (run scripts/format).
• Code lints properly (run scripts/lint).
• Tests pass (run scripts/test).
• Changes are added to the CHANGELOG.

[vincentsarago]

you could also use pure rasterio

import rasterio
from rasterio.shutil import copy
    with rasterio.open("non_cog.tif") as src_dst:
        profile = src_dst.meta.copy()
        
        # update profile (block size, compression,...)
        profile["driver"] = "COG"
        profile["blocksize"] = 512. # example
        profile("blockxsize", None)
        profile("blockysize", None)
        
        copy(src_dst, "cog.tif", **profile)

ref: https://github.com/cogeotiff/rio-cogeo/blob/master/rio_cogeo/cogeo.py#L352-L379

using rio-cogeo would still be valuable if you support rasterio version build with GDAL <3.1