[Feature Request] v-progress-linear add prop to animate the stripes

[mtermoul]

Problem to solve

Currently you can have <v-progress-linear striped ...> which good, however we may also need to have those stripes animated. I propose to add a new prop animate to animate the stripes.

Proposed solution

The new prop should be like this <v-progress-linear striped animate> and the outcome would be something like this
https://codepen.io/mtermoul/pen/yLJVryb