multi-pack-index: add [--[no-]progress] option.

multi-pack-index: add [--[no-]progress] option.

Add the --[no-]progress option to git multi-pack-index.
Pass the MIDX_PROGRESS flag to the subcommand functions
when progress should be displayed by multi-pack-index.
The progress feature was added to 'verify' in 144d703
("multi-pack-index: report progress during 'verify'", 2018-09-13)
but some subcommands were not updated to display progress, and
the ability to opt-out was overlooked.

Signed-off-by: William Baker <William.Baker@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>