Support a stateless configuration by default

Support a stateless configuration by default

Using a stateless configuration, we ship sensible defaults in our vendor-config
file to live in the /usr/share/ filesystem, which is considered to be provided
by the vendor, and to all intents and purposes, read-only.

With this change we can fall-back to the vendor system configuration to
always do the right thing, in the absence of a local system administrator
configuration file in the /etc/ tree.

Notably, this saves users from the potential risks and pitfalls of so called
"three way merges" on upgrades, and offers the immediate benefit that one
can perform a factory reset of the software, simply by removing the relevant
file in /etc/.

This change also resolves a memory leak in the launch code, where a string
allocation was entirely unnecessary.

Signed-off-by: Ikey Doherty <michael.i.doherty@intel.com>