Switch Database with USE statement

[kassah]

Switch database with USE where supported is a more efficient manner than resetting the connection entirely, and retains ability to not reset transaction level (which assists in using RefreshDatabase test trait).

I currently have tested code to do this with MySQL and documented the process for PostgreSQL and MS SQL, SQLite does not support this. If interest is present for this, I would pursue a Laravel PR for adding the database specific functionality, and upon that success, I would look to integrate the generic API from Laravel in this package.

This discussion is to find out from the maintainers if this is a desirable feature, thus worth the effort to PR both in Laravel and here.