Use squishy_cookies to sign and verify user cookies

You can use https://deno.land/x/squishy_cookies to sign and verify cookies

```ts
import { createSignedCookie, verifySignedCookie } from 'https://deno.land/x/squishy_cookies@v0.2.4/mod.ts'

const { headers, cookie } = await createSignedCookie(
'id', '1', 'super_secret',
{ httpOnly: true, path: '/' }
)
return new Response(page, { headers })

// or

const headers = new Headers()
headers.append('set-cookie', cookie)

// Verifying a cookie

headers.append('cookie', cookie) // verifySignedCookie will search for 'cookie' header
const userId = await verifySignedCookie(headers, 'id', 'super_secret')
// userId is false if the verification failed or the cookie value
```