PHP v7.3 upgrade

https://sourceforge.net/p/simplehtmldom/repository/ci/1.8.1/tree/

PHP Warning:  preg_match(): Compilation failed: invalid range in character class at offset 4 in app/lib/composer/wikia/simplehtmldom/simple_html_dom.php on line 1385

Make dist package a bit smaller

https://www.mediawiki.org/wiki/Manual:Developing_libraries#Packagist_guidelines - see 17c40a6

v1.6.1

Remove (and ignore) composer.phar

Composer power

Add composer.json that allows us to:

composer require wikia/simplehtmldom

v1.5

The most up to date version from https://sourceforge.net/projects/simplehtmldom/