Update base_initializr.html.twig

I propose this small change to improve even more this wonderful bundle.

My reasons were:

* Needed a specific version of jquery
* Needed to set up a different place for local copy of jquery
* Didn't want to override the whole foot_script block
* Thought that this blocks add more development flexibility
Merge pull request #860 from davidvartanian/patch-1

Update base_initializr.html.twig