Datetime format

Quickwit's DateTime is a wrapper around Tantivy's provided DateTime type which is internally represented as an i64 microseconds value. For optimization reasons, Tantivy stores the value differently at the following locations:

• DocStore: Dates are stored as they are received from the input document.
• TermDict: Dates are stored with seconds precision.
• FastField: Dates are stored using the DateTime type configured precision that can take of the following values: seconds, milliseconds, microseconds.