Timestamp instant support

[Jefffrey]

See Timestamp with local time zone here https://orc.apache.org/docs/types.html

[Jefffrey]

Writer timezone seems encoded at stripe level, which is problematic if that suggests timezone for a column can vary between stripes since Arrow encodes the timezone in the datatype so would need to be consistent for all data. Need to investigate this more

[Jefffrey]

It seems I misunderstood. According to:

• [C++][ORC] Fix timestamp type mapping between orc and arrow apache/arrow#34590
• GH-34590: [C++][ORC] Fix timestamp type mapping between orc and arrow apache/arrow#34591 (comment)

The writer timezone in the stripe is used for regular Timestamp, as Timestamp instants are in UTC timezone.

[Jefffrey]

Separate note: encoding as Timestamp(Nanoseconds) severely limits the range representable in Arrow, need to keep this in mind

[Jefffrey]

Added by 1888015