Switch to hard tabs for indentation

As per: https://github.com/cloudflare/workers-sdk/issues/1298

wrangler2, and all wrangler templates follow this paradigm for better accessibility by default. It would be great to get a similar `.prettierrc` and `.editorconfig` in this repo. I'm happy to PR this if welcome.

`.editorconfig`:
```
# https://editorconfig.org
root = true

[*]
end_of_line = lf
indent_style = tab
tab_width = 2
```

`.prettierrc`:
```
{
"printWidth": 80,
"singleQuote": false,
"semi": true,
"useTabs": true
}
```