Use slugs.maxlength when generating slugs

[distantnative]

Currently, we often ignore the slugs.maxlength option when generating slugs but rather use the default 128 from Str::slug().

I see two options:

1. Integrate App(null, true)?->option('slugs.maxlength') into Str::slug() to use as default when set. Could this be problematic if someone limits it to a very short length, as we also often use Str::slug() for non-slugs?

2. Create a new, e.g. App::slug() that takes the option and passes it with all the other parameters to Str::slug(). Search through the code where we should use App::slug() instead of Str::slug(). (or Page::slug(), Router::slug() or so).

@lukasbestle @bastianallgeier Which do you think would be better?

[lukasbestle]

I think your point on using the method for other reasons is what counts here. So I think option 2 is better as it doesn't involve a breaking change with hard to overlook consequences.