Change inputmetadata's shape_type, data_type, color_space to string

Change inputmetadata's shape_type, data_type, color_space to string

Those metadata are user unfriendly and difficult to use because of a lack of decscription.
They are changed to string and user can understand what they mean.
The string values are parsed and converted to proper enumerations.

Change-Id: Ia98f29790d68fe2bf2fb38e2e922cc0b9b4d80e4
Signed-off-by: Tae-Young Chung <ty83.chung@samsung.com>