[Rust][DataFusion] Proposal for Basic Timestamp Support

[Andrew Lamb <al...@influxdata.com>]

I am working on an engine for processing  timeseries data. Unsurprisingly
for such a system, values of timestamp type feature prominently and we need
basic support for them in DataFusion.

Initially, we want to use DataFusion with predicates such as '=', '<', '>',
etc on timestamp columns and timestamp literals. For example, finding all
rows in a dataset that fall within a certain timestamp range.

Here is a document with a more formal proposal:
https://docs.google.com/document/d/18O9YPRyJ3u7-58J02NtNVYb6TDWBzi3mIQC58VhwxUk/edit#

Any / all feedback welcome,

Andrew