add assets prefix functionality

[WordsofDefiance]

Hi! I needed this functionality for a project, and after some thought I concluded that the best way to implement it would be to actually add the functionality directly to Scribe.

This allows you to customize the location of the public assets generated for laravel blade documents. By default, the assets are created in public/vendor/scribe. With this feature, if the user defines a laravel.asset_prefix value, the path becomes public/{{ asset_prefix }}/vendor/scribe.

I'm unclear how to best test this (my code currently passes all tests) so I'd be curious for ideas. Open to feedback.

[shalvah]

Hmmm, I'm reluctant to add this in this form. The Laravel convention is to place vendor assets in that public/vendor. If you want to change that, I think I'd favour an approach of customising the assets directory (within public) entirely, not adding a prefix.

[WordsofDefiance]

I made that change you suggested. I renamed asset_prefix to assets_directory, and now the path itself is customizable (within the public directory).

[shalvah]

Please send a PR to the docs repo as well, to update the config reference.

[shalvah]

This page: https://github.com/knuckleswtf/scribe-docs/blob/master/laravel/reference/10-config.md

[WordsofDefiance]

Here's the PR for documentation:
knuckleswtf/scribe-docs#14