[Feature Request] Support for epoch_micros in date formats

[ph-l]

Is your feature request related to a problem? Please describe

I have timestamps which are the number of microseconds since the epoch and would like to display them as dates.

Describe the solution you'd like

https://opensearch.org/docs/latest/field-types/supported-field-types/date/#numeric-date-formats
Add epoch_micros to supported date formats

Related component

Clients

Describe alternatives you've considered

No response

Additional context

No response

[peternied]

[Triage - attendees 1 2 3 4 5]
@ph-l Thanks for creating this issue, want to make a pull request to expose this new format?