app/pdump: add command line options for socket paths

app/pdump: add command line options for socket paths

Since users of the pdump library and tool can chose to have their own
server and client paths, it is must for the pdump tool to use the same
server socket path that was used by primary application while
initializing packet capture framework by rte_pdump_init() or
rte_pdump_set_socket_dir() APIs.

To pass the socket path info to pdump tool a new optional command
line options "server-socket-path" and "client-socket-path" are added.

"client-socket-path" is also added, if the users want to have client
sockets in their own defined paths.

Updated pdump tool guide with the new changes.

Fixes: caa7028276b8 ("app/pdump: add tool for packet capturing")

Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>