telemetry: fix socket path conflicts for in-memory mode

telemetry: fix socket path conflicts for in-memory mode

When running using in-memory mode, multiple processes can use the same
runtime dir, leading to conflicts with the telemetry sockets in that
directory. We can resolve this by appending a suffix to each socket
beyond the first, with the suffix being an increasing counter value.
Each process uses the first unused socket counter value.

Fixes: 6dd571fd07c3 ("telemetry: introduce new functionality")

Reported-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Ciara Power <ciara.power@intel.com>
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Tested-by: Conor Walsh <conor.walsh@intel.com>