Use vocabulary machine name instead of vid

Problem/Motivation

Working with Features allow to export vocabularies for staging and reusability purposes but when deploying on the destination environment we cannot ensure that the vid of the vocabulary will be the same so the settings could be lost.

Proposed resolution

The good practice is to use the machine name instead of vids.

Remaining tasks

• Replace vids by machine names.
• Include an upgrade path.

User interface changes

None.

API changes

Add a helper function to check if a vocabulary is enabled for gmap taxonomy.