make nrmc cmd-run useful again (manifest, LD_PRELOAD, wrappers)

[perarnau]

Bring back the ability of nrmc to instrument an application with nrm-extra tools (LD_PRELOAD) or command wrappers, using the manifest as the driving config.

[perarnau]

We should add a scope to slices, and transmit the slice id when launching through cmd-run. That would allow nrm-extra to use the information to build its scopes.