[Feature Request] Scrim with blur should be easier to set

[J-Sek]

Problem to solve

Setting scrim with blur requires:

• overriding opacity to 1
• setting color with alpha
• custom CSS to set the backdrop-filter value
• repeating those adjustments for VOverlay and VNavigationDrawer

Proposed solution

Since it is very popular design choice, it would be great to have it baked into design system (even if MD3 does not include it in the spec) as app-level variable --v-scrim-blur along with variables for opacity and color.

Optional

Consider naming variables --v-backdrop-* as "scrim" is strictly from Material Design (well.. it depends on how we want to publish non-material "spins" of Vuetify).