power_supply: Charger-Manager: Add properties for power-supply-class

Charger Manager provides power-supply-class aggregating
information from multiple chargers and a fuel-gauge.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>