Provide better documentation on doing "wild" things with IO

[gadomski]

As discussed during the stac-utils working group meeting on 26 June 2023, we could have better documentation around doing "wild" stuff with IO. Things to demonstrate:

• Authentication
• async-wrappers
• ???

@sharkinsspatial were there some other specific cases that you think we could document to help folks out?

[jsignell]

Might be a good opportunity to tidy up how IO works a la stac-utils/pystac-client#552 (comment)