stream-manager-volume: Apply individual volume ratio

stream-manager-volume: Apply individual volume ratio

In Tizen, a stream has one volume type such as media, notification,
alarm. Each type is so-called a volume group which has its own volume
value of a certain volume level. Therefore, all streams that belong to
the same volume group have the same volume value of the group.

This patch adds to calculate volume value including the individual
volume ratio of each stream's volume value to the value of its volume
group.

[Version] 11.1.37
[Issue type] New feature

Change-Id: Ie3099f37ec8f2e513b828bfc11b4dcbdb2572954
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>