* Database isolation: Balancer
Remove naive Balancer
remove debugging lines
Thread dax.Transaction through Controller
Change role to roleType
Swap out Balancer interface with new one
Standardize InvalidTransaction error
Add some interface comments
* Remove type.Worker; replace with type.Address
* Remove database validate from Queryer
This is already being handled in the `CreateTable()` method. Prior
to doing that validation, we were getting a panic, but that's no longer
the case.
* Remove dax.TableQualifier; replace with dax.QualifiedDatabaseID
* Update IDK test to create database
(cherry picked from commit d971cfc269)
* implement CREATE/ALTER/DROP VIEW
* fixed failing test
* another failing test
* fixed some broken serverless tests
(cherry picked from commit c620aae350)