feat(VTimePicker): Add keyboard controls

[ikushum]

fixes #10722, #21885

Description

• Convert the hour, second and minute divs to buttons
• Add keyboard controls and navigation

Markup:

<template>
  <v-container>
    <v-time-picker
      v-model="model"
      use-seconds
    />
  </v-container>
</template>

<script setup>
  import { ref } from 'vue'

  const model = ref()
</script>

[J-Sek]

The immediate problem becomes - assistive tools will show the clock has 12 options for minutes and seconds with gaps. Not sure if VBtn approach is correct here. Maybe the clock should have role spinbutton and accept up/down keys to change, while the visual representation is more of a guide for people relying on pointer-based interaction.

[J-Sek]

Outline would definitely help convey the clock is focused. Background color difference is barely visible.

[J-Sek]

Existing projects might have some customization on .v-btn that could unintentionally leak here. Since the styles would need to be slightly reworked for v4, maybe we should push it all to next?

[J-Sek]

The claim "because tests look ugly" is too weak to justify the risk unintentional styling accidents. E.g. user can make all VBtn have strong shadow and even supplement custom CSS, just to later realize it leaks into this component.

Everything else looks good and we could merge without VBtn.