Figure out the preferred pattern for interacting with schema

[russellpierce]

A lot of R database tools tend to assume that you're just going to execute against the active schema. {dbplyr} goes a step better with in_schema()... but in general, I think it is good to set out an opinion re: how functions like rs_create_statement() should be called if creating a table in the non-default schema. Argument names like 'table_name' might sort of hide the functionality... on the other hand having a separate schema arg might be heavy.

[JakeRuss]

I'm sure we can accommodate that @russellpierce. I want to get the package into functioning state before I start making changes to the interface but I think this a desirable change.

Which, if you install my branch and set your environmental variables, I think you'll see a performance increase to these jobs already. I wouldn't claim it as bulletproof yet, but I did see a 2.5x speed increase on the transfer and loading.