Changes for the vibra plugin and workflow

[garsua]

Modify the AUTHORS file to include the author of the vibra plugin and workflow

Modify the setup.json file to include the vibra plugin and workflow
dependencies

Add vibra plugin and workflow files

Add files with example calculations for the vibra plugin and workflow

Modify the documents to add new vibra plugin and workflow sections

[garsua]

@garsua Added vibra parser and modified setup.json and vibra calculation plugin 3cc9602 @garsua Modified examples, workflow and parser and added buildsc.py 09c0afa @garsua Changed definition of K-points for bands