Closes: #2321

Note: The code works without this as we will not process more headers.

This change allows setting the codec for playlist and RoarAudio input.
It allows setting vorbis and generic Ogg for playlists (all types).
For RoarAudio the ogg_generic type is now mapped to IceS' generic OGG type.

This update allows later on adding of more codecs.
A generic Ogg type for the stream also got defined. Using that type
we can not alter the stream. But as long as we know the sample rate
we can still serve it to the server.

This removes the unused function config_dump().
it likely was there for debugging the config parser. At best it was
incomplete after years not not being used.

The configure autoconf file should be named configure.ac not
configure.in

This fixes some of the autogen.sh warnings about usage of deprecated
INCLUDES.

This includes the <username> tag in the docs.
Closes: #2207

This commit updates code and docs to the rename of libshout
function names. See commit b8869ac507eca12f75bd2ee028230ddaf5d879eb
of libshout for more details.

This exposes TLS options of libshout via config file.
Documentation has been updated but example config files have been
left out. They should be updated as well. Keeping in mind not to
blow them up too much.

See: #2152

Start using submodules
Changed Makefiles accordingly
Changed header includes accordingly