Prop for control over tabindex of PopperContent

[kenneth-hendricks]

Sometimes it's not desirable to have the popper content be tab-able , e.g. in the case of using floating-vue to create dropdown menus. It would be great to have more control over this.

In my case, i still want auto hide to function correctly but still be able to set the Popper Content to have no tab index.

Line in question:

https://github.com/Akryum/floating-vue/blob/b85e1698e631ced7d2d3ae3892c2f28e5f701b84/packages/floating-vue/src/components/PopperContent.vue#L26