platform/rde1edge: run_model script bug fixes and refactoring

Fix bugs related handling of the model binary path, passing the correct
set of model parameters and handling model launch failuers. While at it,
refactor the handling of parameters for handling automated runs.

Change-Id: I63a8e3530b689b57ff63ad8708022df8e94d69f6
Signed-off-by: Lokesh B V <lokesh.bv@arm.com>