Update documentation!

[benkeen]

The vimeo video no longer exists.
https://docs.formtools.org/modules/form_builder/

[paulied661003]

The most appealing module for me is the form builder which try as I might I cant get to show up in the form tools module list, I am pretty shure I've used all the online acvice I can find.

I've downloaded it, created the folders, unzipped, ..... updated module list......