[FAB-14765] Expose SendBufferSize in cluster config
[FAB-14765] Expose SendBufferSize in cluster config

It is tied strongly to MaxInflightBlocks which is exposed,
so we should expose it as well.

Change-Id: I9cf49001eb1ebce89ddb7d969496d48c15a7e182
Signed-off-by: yacovm <632344b5da9bd743456189af4db4b56472defb8c@il.ibm.com>

xixuejia/fabric,xixuejia/fabric,xixuejia/fabric