Suggest FANTOIR_TABLE value in fetch command

Summary:
Currently, the fetch commands prints:
FANTOIR_FILE=FANTOIR1022

With this change it also prints:
FANTOIR_TABLE=fantoir_202210

Use case

That allows pipeline to do something like:

$ fantoir-datasource fetch > .env
$ source .env
$ fantoir-datasource import $FANTOIR_FILE $FANTOIR_TABLE
[...]
$ fantoir=datasource promote $FANTOIR_TABLE

Ref T1750.

Test Plan: fantoir-datasource fetch

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1750

Differential Revision: https://devcentral.nasqueron.org/D2753