Update bedrock-autoloader.php

Call load_plugins() method on construct instead of the plugins_loaded hook

The mu-plugins are actioned before normal plugins in the action order. Some mu plugins are required
The bedrock-autoloader mu-plugin seems to fulfil two purposes. it a) allows the use of composer to make mu-plugins dependancies by running mu-plugins from within directories. b) allows normal plugins to act like mu plugins. However by running the mu-plugins further down the action order list, neither mu-plugins or plugins are behaving exactly as standard mu-plugins do as standard in wordpress. This could be important if the mu-plugin you are requiring via composer does some setup that normal plugins will then use. In the current implementation it will be loaded after the normal plugins.