Support authorization in DBC Feeder

[lukasmittag]

Maybe give the ability to say 'I want to use dbc feeder with authorization' and 'No, I don't want authorization'
For authorization what needs to be done is:

• Add new parser argument here: https://github.com/eclipse/kuksa.val.feeders/blob/a95ad4c90c11c3c90185b4fc4dfe71dd4e7f3b1c/dbc2val/dbcfeeder.py#L386
• Extend to enforce authorization if wanted : https://github.com/eclipse/kuksa.val.feeders/blob/a95ad4c90c11c3c90185b4fc4dfe71dd4e7f3b1c/dbc2val/dbcfeeder.py#L173
• Provide the right token file. Maybe add a parser/config argument for this. And think about a good default token (allow everything?or is it too much)

[erikbosch]

Work ongoing in #74

[erikbosch]

#74 merged, closing this one.

Note that solution relies on kuksa-client v0.4 which so far only exist as pre-release