TypeGPU endpoints

[aleksanderkatan]

Right now, tgpu, std and data are available on different endpoints. It is not uncommon to see the following in code:

import tgpu from 'typegpu';
import * as d from 'typegpu/data';
import * as std from 'typegpu/std';

I propose that we export all those from the same endpoint, so it becomes:

import { tgpu, d, std } from 'typegpu';

Pros and cons that I see:
[+] less lines of code in a typical usage,
[+] we impose a naming convention for d and std,
[+] std already depends on data,
[-] major breaking change,
[-] core does not depend on data (however it is almost exclusively used with data),
[-] data is currently independent from core and std (unless #1486 is merged).