Internal libraries removed.

CMake will now only use external libraries, and local copies
have been removed. This means from now on you will need to
install MySQL/MariaDB, OpenSSL, zlib, and bzip2 prior to
building *mangos-one*.

This is a one-time process, and will reduce build times for
future builds, and also removes issues with having these
libraries already installed on your system.

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>