Add empty scraper for the dossiers of the Chamber

This mainly sets up the getProviderArguments() implementation.
[composer] Require patchwork/utf8

Patchwork UTF-8 for PHP
https://github.com/nicolas-grekas/Patchwork-UTF8

Extensive, portable and performant handling of UTF-8 and grapheme clusters for PHP.

This is a dependency of `illuminate/support` but the package wrongly references it as a dev dependency instead of a normal one. Explicitly listing it in the main composer.json fixes the issue.
Add previousOne() and nextOne() to custom crawler

These are efficient and readable shortcuts to get the same results than `$crawler->previousAll()->first()` and `$crawler->nextAll()->first()`.
[doc] Fix return value in docblocks

Also fix a missing space between two words.
Add magic `__toString()` method to custom crawler
DRY the custom crawler a bit by extracting a throw
Remove `api` tag from docblocks in custom crawler

Kids, you should always be careful when copy-pasting stuff.
Add K/Dossier/HtmlToXmlConverter

This converter takes the HTML source of the complete page of a dossier and transforms it to an XML tree, thus making it easier to work with.
Add K/Dossier/XmlToArrayConverter

This converter takes an XML tree of the complete page of a dossier and transforms it to a native array-based PHP structure.
Make scraper return data of dossier as a PHP tree

The HTML source of the dossier is converted to PHP in two distinct steps.

1. HTML -> XML
2. XML -> PHP

The result is then returned by the scraper.
Starts to document the K scraper of dossiers
[fix] Options were not passed correctly in example

The readme file said that `scrape()` methods could accept an array of arguments. This is not true anymore.

This change fixes this error and provides an example of how to set options on the scrapers.
Merge branch 'k-dossier-scraper'

Already merge some work in master branch

Conflicts:
	README.md