EX-4583 lipe: show all lpcc information in 'lpcc status' command

EX-4583 lipe: show all lpcc information in 'lpcc status' command

Collect lpcc config, lpcc_purge stats, and lustre stats related to
lpcc to together and show in 'lpcc status' command. 'lpcc status-all'
is an alias of 'lpcc status'. The output of 'lpcc status' looks like:
{
    "/mnt/lustre": {
        "pcc": [
            {
                "mount": "/mnt/lustre",
                "cache": "/mnt/pcc",
                ...
            },
            {
                "mount": "/mnt/lustre",
                "cache": "/mnt/pcc2",
                ...
            }
        ],
        "fs_stats": {
        }
}

Change-Id: I032763fb3b45646330b13f5cef34ce8658bddfe4
Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial testlist=sanity-pcc
Reviewed-on: https://review.whamcloud.com/46191
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>