LU-930 doc: update MAINTAINERS and mailmap

LU-930 doc: update MAINTAINERS and mailmap

Change cray emails with new hpe.
Add new reviewers from HPE.

Change-Id: I7b5b3270fa16beec84c50ffdf4dc0fb7f85db761
Test-Parameters: trivial
Signed-off-by: Sergey Cheremencev <sergey.cheremencev@hpe.com>
Reviewed-on: https://review.whamcloud.com/37549
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>