Create minimal functionality LS2 methods for addl information

:Release Notes:
Other components can request information about current available
shards from DB8 via LS2

:Detailed Notes:
 - Request list of active media and receive a JSON object:
  method name:  listActiveMedia
 - Request information on a DB8 by providing the shard ID:
  method name:  shardInfo
 - Request whether an external media supports a specific kind,
       by providing the DB8 short ID and the Kind
  method name: shardKind
 - Mark external media as 'transient' by providing the DB8 short ID:
  method name:  setShardMode

:Testing Performed:

:QA Notes:

:Issues Addressed:
[GF-3562] DB8 Ext: Create minimal functionality LS2 methods for shard information

Open-webOS-DCO-1.0-Signed-off-by: kyouhyun.hwang <kyouhyun.hwang@lge.com>
Open-webOS-DCO-1.0-Signed-off-by: Roger Stringer <roger.stringer@lge.com>

Change-Id: I7b4427b55d49898a4ffd675d189be9fd6c4c669a
Reviewed-on: https://g2g.palm.com/3085
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Tested-by: Roger Stringer <roger.stringer@lge.com>