add override for npm:bootstrap@4.0.0-beta

[bbak]

Replace Tether with Popper.js, see bootstrap#22444

[aluanhaddad]

Hi, thanks for the PR.

There is actually already one open for bootstrap@4.0.0-beta but it needs some work.

The dependencies unfortunately need to be moved to peerDependencies

I tried this override locally, after changing them to peers, and found the same issues with popper.js as in the other, #1056.

A problem is that although popper.js is a well behaved package, only registering itself globally as a last resort, bootstrap is emphatically not. It requires that a global variable named Popper exist or it fails. To make matters worse, bootstrap depends on popper.js as a peerDependency causing pollution for all users of that package even if they are not using bootstrap. This may be something that we have to live with.

I believe that, unfortunately, the only way to get this working is to add an override that globalizes popper.js.

For more information, checkout the comments on #1056

[aluanhaddad]

It looks like the next beta release will include Popper.js in the bundle itself which will make this easier.