Add options: optionally skip calculating of min/max via tiling

[DanielJDufour]

Sometimes people will want to try to grab the min/max value from the GDAL_METADATA (if it exists), but won't want to wait to get the min/max by grabbing every tile from a COG's overview or raw data if no overview exists. (This can take roughly 15 seconds for Landsat overviews).

Here's a possible API solution:

const { bands } = getStats(image, { quick: true });

Alternatively, a user could specify what percentage of tiles to sample (defaulting to 1.00 for 100%). In the following example, we sample roughly 50% of the tiles:

const { bands } = getStats(image, { sampleSize: 0.5 });

If a user doesn't want to sample any tiles, they can use:

const { bands } = getStats(image, { sampleSize: 0 });