Summary
The "local_store" module implements a storage_source interface, and is used by tiered storage to emulate a cloud storage.  The word "local" is used in various other contexts of tiered storage discussions and modules.  For example, we can say something is "locally stored".  So having the name "local_store" can be confusing at times, and it seems best to rename it.

Motivation

• Does this affect any team outside of WT?
  No, it is specified in various tests that are run within WT.

• Is this issue urgent?
  This is not urgent, but as we start to ramp up on other tiered storage work, it would be good to to have "local" overloaded.

Acceptance Criteria (Definition of Done)
When will this ticket be considered done? What is the acceptance criteria for this ticket to be closed?

• Functionality: all references to the local_store module must be changed in tests and documentation.
• Testing: a_ll unit tests must pass._
• Documentation: references in documentation must be updated.  As yet there is no architecture guide for the local_store.