Enable the usage of an alias for a column name when using Sorts

[dominikb]

This PR addresses #163

I'm not too fond of the solution here

if (is_string($alias)) {
    return Sort::field(ltrim($alias, '-'), ltrim($sort, '-'));
}
return Sort::field(ltrim($sort, '-'));

Maybe someone can come up with a more readable solution?

[AlexVanderbist]

Hey, thanks for another PR! Am I missing something or are there some changes to the Sort class missing?

[AlexVanderbist]

I've added the missing code in Sort.

About that is_string clause that you don't like; I wouldn't mind just dropping the allowedSorts(['sort' => 'alias']) array notation.
It's not supported for filters either. If you want to use any aliases you'll have to use the Filter and Sort classes which will be type hinted. This way there's no "magic" array syntax where you're unsure about whether the key or the value will be used as an alias, etc...

Lmk what you think :)

[dominikb]

Hey, thanks for the help there. I somehow forgot to commit half of my files 🤕

I like it better to use the actual Sort classes when aliasing a column. As you mentioned, it is more expressive in what it actually does and can be comprehended easier.

Thus I've decided to drop the array syntax and remove tests for it.

I've also updated the documentation to reflect theses adjustments.