Exposing procket:dev/ with options support

[meox]

@msantos can you merge this?

[msantos]

Thanks @meox

I went ahead and merged the commit but with some reservations:

• as commented in the tunctl PR, tunctl could have called procket:open(0, [{dev, Dev}, {namespace, ..}, ...]) directly
• please add a commit message explaining the change

Something like:

procket:dev/2: support passing options

Add procket:dev/2 to allow opening a device in a network namespace on Linux.

• please move whitespace and formatting changes to a separate commit. Use erlfmt for re-formatting code.