build: add makefile targets to build DPDK and VPP

Add makefile targets to build DPDK, VPP, and to build all the components.
With this the build.sh is not required. This will make building the
code and the documents look similar.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Nathan Brown <Nathan.Brown@arm.com>
Reviewed-by: Tianyu Li <tianyu.li@arm.com>

Change-Id: I2d9ced7cc7a6a275463a0ad1546f14a4ed8202e1