gstsctpclientsink: Check out the number of streams used before accepting more pads

Change-Id: I2571d4f9849976f9a14e439b8487c7c6a2ccba23
gstsctpclientsink: Configure SCTP socket

Change-Id: If5b6110b1ce523eee8341d4375c973bffd771609
sctp: Change logic of classes

This patch moves logic implemented in gstsctpclientsink to gstsctpbasesink and
viceversa. In this way, gstsctpbasesink is just a container of gstsctpclientsink
elements which can manage by themselves SCTP sockets. gstsctpbasesink is a bin
than manages a gstsctpbasesink for each stream that is connected to it.

Change-Id: I247ecd959913395887d5580890a33d2247453255
gstsctpclientsink: Add properties

Change-Id: I21a1ea3d224e3a37601bedd5b04ac90b1403ddc1
gstsctpclientsink: Implement some basesink methods

Change-Id: I5adfdc87b4b319ead39f12210c21a1d7e3f28513
gstsctpbasesink: Configure sctp clients sink's sockets when transiting to READY state

Change-Id: I65bbdf5ff6c00fcdea37604859708ce125b8cc33