build(vite): replace webpack with Vite, add Typescript (#1594)

BREAKING: mixins are no longer exported from the index (and will likely be converted to hooks)

tests/unit/Ajax.spec.js

@@ -1,6 +1,7 @@
-import { selectWithProps } from '../helpers'
+import { it, describe, expect } from 'vitest'
+import { selectWithProps } from '@tests/helpers.js'
 import { shallowMount } from '@vue/test-utils'
-import vSelect from '../../src/components/Select'
+import vSelect from '@/components/Select.vue'
 
 describe('Asynchronous Loading', () => {
   it('can toggle the loading class', () => {