Extracted from: https://github.com/rails/rails/pull/50793

Right now quoting table or column names requires a leased Adapter
instance, even though none of the implementations actually requires
an active connection.

The idea here is to move these methods to the class so that the quoting
can be done without leasing a connection or even needing the connection
to ever have been established.

I also checked `activerecord-sqlserver-adapter` and `oracle-enhanced`
gems, and neither need an active connection.