feat(calendar): prop to switch between dynamic/static number of weeks

[nekosaur]

Description

looking at previous art, most "fullscreen" calendars seem to go with a varying week length of either 5 or 6 depending on how the days in the month are arranged. this includes arguably the two biggest examples (google, microsoft). but there are ones that use a static 6 weeks, pretty much always together with showing adjacent days.

date-pickers also vary, but ones based on material design like MUI do use static 6 weeks so that the dialog does not jump when switching months

with this change, date-picker uses static by default, calendar uses dynamic

Markup:

<template>
  <v-app>
    <v-container>
      <v-date-picker />

      <v-calendar
        v-model="date"
      ></v-calendar>

      <v-calendar
        v-model="date"
        weeks-in-month="static"
        show-adjacent-months
      ></v-calendar>
    </v-container>
  </v-app>
</template>

<script>
  import { ref } from 'vue'
  export default {
    name: 'Playground',
    setup () {
      const date = ref([new Date()])
      return {
        date,
      }
    },
  }
</script>