common: Add singleton utility
common: Add singleton utility

This patch adds a utility func called singleton if any
class is decorated as singleton, such a class will
behave equivalent to java singleton.

Change-Id: Ibf86424ee4f5718965cae3cae89cc788f301a920
Signed-off-by: anmolbabu <3d38fb1e9c5ff2662fc415254efcdfedb95b84d5@gmail.com>

Tendrl/commons,rishubhjain/commons,r0h4n/commons