Create a type-safe string join utility which can be used like so:
```ts
const hyphenJoiner = join('-')
const result = hyphenJoiner('a', 'b', 'c'); // = 'a-b-c'
```
Or alternatively:
```ts
join('#')('a', 'b', 'c') // = 'a#b#c'
```
When we pass an empty delimiter (i.e '') to join, we should concat the strings as they are, i.e:
```ts
join('')('a', 'b', 'c') // = 'abc'
```
When only one item is passed, we should get back the original item (without any delimiter added):
```ts
join('-')('a') // = 'a'
```
