Re-name postgres-schemas dir to raw-tables

[psivesely]

No description provided.

[conorsch]

This doesn't seem to affect anything at all, but if it's a more intuitive name, than I suppose it makes sense. @redshiftzero do you concur with the terminology proposed here?

[redshiftzero]

Well if we want to rename it then it should probably be called just postgres-tables or database-tables since after the merge of #57 that directory contains more than just create table scripts for the raw schema

[conorsch]

Fair point. Let's create intuitively named subdirectories in the files/ dir so it's obvious what goes where. The tasks can be trivially updated to handle the new filepaths.

[psivesely]

Fixed in 33be2d7!