feat: Nanosecond timestamps [WIP proof-of-concept for protocol RFC]

[itamarst]

This is a proof-of-concept of adding nanosecond timestamps, part of a protocol RFC: delta-io/delta#6081

There is a corresponding PR against delta-kernel-rs: delta-io/delta-kernel-rs#1897

Future work that would need to be done:

• Deciding whether nanosecond timestamps should be supported by default.
• Previously nanosecond timestamp columns were automatically converted to microsecond. This changes the behavior to preserving them as nanosecond. I can imagine a desirable behavior being keeping the old auto-conversion if the nanoseconds timestamps table feature is disabled. The current tests were updated with assumption that nanosecond stays as nanosecond, but that may be annoying for users who use multiple libraries and who suddenly and unexpectedly have tables with unsupported nanosecond timestamps.

[github-actions]

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