Introduce common service client

In preparation for making common service access information
such as the maximum request length or supported serializations,
a common service client has been introduced that standardizes
common client state, including any available service access
info.  All clients refactored to use the common service client.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I31336901476f5647d2ed00294716940f475da08c
46 files changed