tools/e2g.ps1: allow pubkey usage via pageant (#143)

* Set different arguments for plink if we use peagent.
* MailboxExportRequest: Use $MBX.Alias for safer handling.
  Extend INFO with Exchange Version Check
* Add Information how to use a persistent mount via fstab.
* Use full cmdlet names rather than shorthands
* Add Information on how to use gromox-mbop to clean any data from
  previous import tests.
* Allow Import/Ignore list be controlled via fileimport.

Author: crpb