Export structured time values

[simolus3]

For DATE, DATETIME, TIME and TIMESTAMP types, this package offered two options:

• Exposing them as a JavaScript Date, which looses sub-millisecond precision.
• Exposing them as text, which uses the builtin Date formatting, making values harder to parse than necessary.

Since this package is mainly used in the sync service, this changes the implementation to unconditionally emit those types as structures. This will allow the sync service to render time values into a format understood by SQLite with full control over the exact format.