Use the types registry for INFORMATION_SCHEMA.TYPES, etc.

Also clean up use of mcompat in the same places.

This changes things in slight, but I believe defensible, ways:
* Unsigned is next bigger integer size, not number of unsigned bytes.
* Date & time are 4, not 3 bytes.
* Decimal is not fixed size.
* Sort order is by name, but by bundle and then name (boolean is in with the other b's).
* Type names in attributes table are upper-case for consistency.

I imagine FTS will need to react. But probably after the rest of this work has settled in.