Support google.type.(date|datetime|timeofday)

[derekperkins]

There is already native helper support for google.protobuf.Timestamp, and while google.type.* aren't WKTs, they're pretty close. Since it will all be coerced to a JS Date, similar helpers could be provided for these three types.

cc @tannerlinsley

[timostamm]

Thanks for the request, Derek, also for the related #226.

Conversion between DataTime and a JavaScript Date object might be the lowest hanging fruit here, although it may be non-trivial to support IANA timezones (the only standard API is buried in Intl.DateTimeFormat).

[xmlking]

I also shared the inconsistent behavior when using google.type.*

connectrpc/connect-es#262