Add tutorial for creating Landsat 8 STAC

[lossyrob]

This PR adds a tutorial for creating a STAC of a subset of Landsat 8 data from AWS.

This tutorial:

• reads a list of scenes from AWS
• creates a subset of scenes based on a location and year
• Reads relevant metadata from the MTL and ANG files for a scene to create an Item per scene, including information for the eo, projection, and view extensions.
• Creates a Collection of the scene Items.
• Writes out the STAC locally
• Servers the STAC out for usage in stac-browser.