Pre role hardware check

[Wenzel]

This PR renames the role default_vars_only to pre_role, and moves fuzzer pre_tasks to pre_role, in order for the hardware check to be done ASAP when the playbook executes.

Helps to solve https://github.com/IntelLabs/kAFL/issues/86

[il-steffen]

Thanks. pre_role is not very expressive, maybe call it pre_checks or pre_setup?

[Wenzel]

Thanks. pre_role is not very expressive, maybe call it pre_checks or pre_setup?

I would have but this is missing the fact that it defines global variables for the whole collection. I opted for pre_role to be more generic, but if we can find something more expressive.. ?

What about a common_setup role ?

[il-steffen]

I still like pre_checks (like pre flight checks). :-)

[Wenzel]

Renamed to pre_checks