comp-manger: Send/Receive buffered data instead of string

comp-manger: Send/Receive buffered data instead of string

Application can send buffered data with length, sending it as string
incomplete data would be received. This patch sends data as string after
encoding it to Base64 and on receiver side decodes it before providing
data to upper layer

Signed-off-by: Saurav Babu <saurav.babu@samsung.com>