[META] Provide default webform component groups with prefill capabilities (DVGWF)

DvG webforms will get an improvement by using tokens which are populated using a SOAP service using the StUF-BG standard. These tokens can be used in webforms to prefill fields.

Also, we want editors to be able to re-use predefined "webform collections". These are groups of components, with their settings and conditionals, which can easily be added to new forms.

There are 4 new contrib modules which add all the functionality:

dvg_stuf_bg
https://www.drupal.org/project/dvg_stuf_bg

dvg_stuf_bg_tokens
https://www.drupal.org/project/dvg_stuf_bg_tokens

dvg_webform_component_collections
https://www.drupal.org/project/dvg_webform_component_collections
Contains a user interface for creating collections of components, including there settings (like prefill). A group of components (including their conditionals) can be inserted into a new webform, thus greatly reducing the time to create forms and increasing user experience.

dvg_webform_components
https://www.drupal.org/project/dvg_webform_components
These contain all the special DvG webform components. In particular the new "address" field which has prefill/validation capabilities with stuf-BG and much more!

This issue is to keep the main discussion about this feature (codename DVGWF) centralized and optionally create sub-issues for this task.

Issues:
#2750143: Add DVGWF modules to DvG makefile

Testing / feedback:
Feedback is welcome! The recommended way to test this is updating the makefile (see issue above) and build a new DvG. Enable the modules which can be found in the "beta" package. Also please see the separate README.txt files of each module.
Any bugs should be reported in the correct project issue queue if possible.