Proposal to remove HTTP config file

No more `chef-client -c http://blah.com/client.rb`, because it is probably not being used, has at least a couple of actual bugs, can be done explicitly by users if they really want it, and has a bunch of code that can be removed.
`Chef::HTTP::Simple` can probably make that easier and it should support `trusted_certs` (our workaround for making self-signed certs less of a PITA).