Add space-before-function-paren

Since we tend to prefer:
```js
function hello (name) {
    return 'hello ${name}';
}
```
as oppose to 
```js
function hello(name) {
    return 'hello ${name}';
}
```
I suggest we add [`space-before-function-paren`](https://eslint.org/docs/rules/space-before-function-paren) to our base `.eslintrc`.