MAINTAINERS: Update entries from the Nitro Enclaves section

Update the list of maintainers for the Nitro Enclaves project. Alex
(lexnv@) is not working at Amazon anymore and there will be the same
case for me starting with 2023.

Add a reference to the mailing list of the Nitro Enclaves development
team.

Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
Acked-by: Alexandru Vasile <acvasile96@gmail.com>
Link: https://lore.kernel.org/r/20221108185912.15792-1-andraprs@amazon.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>