feat: vue composition api use (Rollup issues)

[davidjbradshaw]

Atempt to fix @divine #1364 PR

Issue is that Rollup won't accept TS in a .vue file. To fix this, I have

• Changed @rollup/typescript -> rollup-plugin-typescript2
• Changed packages/vue/index.js -> packages/vue/index.ts
• Added @rollup/plugin-alias with alias({ entries: [{ find: /^@\/(.+)/, replacement: './$1' }] }),
• Added @vue/tsconfig": "^0.7.0
• Added packages/vue/vue.d.ts
• Added tsconfig.json

Yet Rollup still refuses to read the .vue file with TypeScript.

packages/vue/index.ts → dist/vue/index.umd.js, dist/vue/index.esm.js, dist/vue/index.cjs.js...
[!] (plugin rpt2) RollupError: packages/vue/iframe-resizer.vue?vue&type=script&setup=true&lang.ts (7:5): Expected ';', '}' or <eof> (Note that you need plugins to import files that are not JavaScript)
packages/vue/iframe-resizer.vue?vue&type=script&setup=true&lang.ts (7:5)