[11.x] Add prependLocation method to View Factory

[nshiro]

This PR adds the prependLocation method to the View Factory.
This is useful if you want to prepend paths using the View Facade.

Before

use Illuminate\Support\Facades\View;

After

Illuminate\View\ViewFinderInterface doesn't have prependLocation. However, I'll leave it as is since adding it could be a breaking change if someone implements it.

[shaedrich]

Shouldn't addLocation() be appendLocation() then? And since it is not, wouldn't it have been better to add a flag the turns appending into prepending to addLocation() to stay consistent?

[nshiro]

I think addLocation() would have been better.
However, I personally think it is simple enough as it is.