Move date/time `SerializationFeature`s into `DateTimeFeature` (3.0)

[cowtowncoder]

With #5032 Java Time module (jackson-datatype-jsr310) was merge into jackson-databind. Its configuration settings were renamed DateTimeFeature, to be used for all date/time configuration (f.ex for Joda module).

But there are a few existing SerializationFeatures that would make more sense as more specific DateTimeFeatures. Let's make them. This includes:

• WRITE_DATES_AS_TIMESTAMPS (false)
• WRITE_DATE_KEYS_AS_TIMESTAMPS (false)
• WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS (true)
• WRITE_DATES_WITH_ZONE_ID (false)
• WRITE_DATES_WITH_CONTEXT_TIME_ZONE (false)
• WRITE_DURATIONS_AS_TIMESTAMPS

Defaults (shown in parentheses) can remain for now: if changes desired let's handle them under separate issue.