Add @react-email/components to the documentation

[andrecasal]

Goals

Improve documentation around component installation and usage.

Background

One generally has to import multiple components from react-email. At the moment the documentation recommends we install and import every component independently:

npm install @react-email/container -E
npm install @react-email/html -E
npm install @react-email/link -E
npm install @react-email/tailwind -E
npm install @react-email/text -E

and

import { Container } from '@react-email/container';
import { Html } from '@react-email/html';
import { Link } from '@react-email/link';
import { Tailwind } from '@react-email/tailwind';
import { Text } from '@react-email/text';

The documentation should reflect a more streamlined approach.

Proposal

I recommend the documentation reflect this instead:

npm install @react-email/components

and

import { Container, Html, Link, Tailwind, Text } from '@react-email/components'