Always load a separate copy of jQuery w/ AMD compatibility

This build's on #541, but adds fixes functionality for use along side AMD projects. With DjDT's current module structure, the only way to truly support this is modifying a copy of jQuery itself to add a namespace:

#541 used added a namespace for DjDT's version of jQuery. jQuery's inner define call ([see source](https://github.com/djfarrelly/django-debug-toolbar/blob/12149d4b5b12bbcba84261dc36d932e5959a481e/debug_toolbar/static/debug_toolbar/js/jquery.js#L9074)) still registered jQuery as 'jquery'. We change this to "djdt.jquery" so DjDT modules like [toolbar.js line 4](https://github.com/djfarrelly/django-debug-toolbar/blob/12149d4b5b12bbcba84261dc36d932e5959a481e/debug_toolbar/static/debug_toolbar/js/toolbar.js#L4) will load that.

Additionally on line [9110](https://github.com/djfarrelly/django-debug-toolbar/blob/12149d4b5b12bbcba84261dc36d932e5959a481e/debug_toolbar/static/debug_toolbar/js/jquery.js#L9110) of our modified jQuery, I assigned jQuery to `window.djdtjQuery`to avoid the need to use `noConflict` in `base.html`.

**Note**: I know modifying the jQuery source may be viewed as something not to do, but for the time being, this will make sure that DjDT's jQuery does not conflict with the end user's jQuery or an AMD project. In my opinion, the best way to avoid all issues across the board would be to refactor DjDT without jQuery, but that would take some time.

PS - I'm not sure if I made this pull request correctly to build on and cite @aaugustin's PR (#541). I didn't mean to duplicate his work, only amend it.