convert most ENUM types into Tables

[andrewharvey]

Most/all of the ENUM types in 01-create-datatypes.sql should be converted to tables in the same way as census_2011.religious_affiliation is done. This means the long name can exceed 63 characters, and our data tables still only need to reference on a 2 byte smallserial.

It also allows us to attach extra information to each of the, previously ENUM values, such as their Census Dictionary/ABS Classification code.

[andrewharvey]

made some progress recently. only a couple of tricky ones are left.