[config] Unite the various *.ini files

We have a bunch of configuration files: hue.ini, hue-beeswax.ini, hue-shell.ini. While it's useful for SDK apps to be able to ship their own configuration files, the Hue project itself should only have one conf file. It'd be easier to manage, and users won't have to look in multiple places to check how things are set up.

Note that this affects upgrading users. For example, they will have an old hue-shell.ini, but the [shell] section will also be in hue.ini.