Allow multiple vocabularies in the taxonomy filter

Problem/Motivation

Field UI allows you to select multiple target bundles for a field.
When you get to the views UI though you can select just a single vocabulary. For some usecases this is a problem

Proposed resolution

Allow to set multiple vocabularies

Remaining tasks

• Write a proper update path
• Write a test for the new capability
• Write a test for the update path

Before:

After: