Evaluate the new MountManager feature of Flysystem v3

Problem/Motivation

Flysystem v2/v3 introduced a new "MountManager" adapter, that basically allows for easier management of multiple schemes that utilize the same base adapter, and provides a more efficient way to process assets associated with those schemes.

However, this may run counter to the way that the Drupal Stream Wrapper manager manages schemes.

The MountManager feature of Flysystem v3 needs to be evaluated to determine if it could be leveraged within the Flysystem module for Drupal without overly complicating things.

https://github.com/thephpleague/flysystem/blob/3.x/src/MountManager.php
https://github.com/thephpleague/flysystem/blob/3.x/src/MountManagerTest.php