Add documentation about bootstrap global var

[Johann-S]

Since our beta 2 and now in beta 3, we have a bootstrap var available in the global scope, which allow folks to do for example :

bootstrap.Util.getUID('test')

So we should add that somewhere in our documentation

[mstill3]

I can handle this

[hembhagat99]

Hello @Johann-S . I would like to start contributing to bootstrap. If @mstill3 is not working on this issue, I would like to work on this.

[mdo]

Imagine this should go on https://getbootstrap.com/docs/4.5/getting-started/javascript/. What should be documented, if this is still relevant?

[XhmikosR]

That everything is under the window.bootstrap object. Unsure what and how to document this, but we should do it eventually.