A separate crate for common types such DataType and Value

A lot of times when using/implementing an ORM there is a lot of enum matching which DataType should be matching to essentially the same data type for the ORM implementation which ultimately maps to the underlying database DataType. There would be also conversion of Value to and fro ORM enum Value. If we can move these common types into a thin shared crate, it would remove a lot of conversion code. One example where is this applied is the `http` crate which is used in `hyper`,`actix`,and `reqwest`

The issue names DataType and Value but no files or tests. First locate their definitions and the ORM/database conversion paths, then define the shared crate boundary; the work is complete when the common types can be reused without duplicated conversions.

Written by the indexing model from the issue text.