Don't compile the packet within basalt-server

- Remove the compilation of the packet from basalt-server once https://github.com/basalt-rs/bedrock/issues/18 is complete.
- Add a new _optional_ CLI argument which accepts the path to the packet PDF that should be served at `/competition/packet.pdf`
- Add endpoint at `/competition` that will give information about the competition (i.e., version, whether the web server is hosted, _whether there is a packet download_)

Start by reading the basalt-server CLI argument handling and the competition HTTP routes, then check issue #18 before changing packet compilation. The work is done when packet compilation is removed, an optional packet PDF path serves /competition/packet.pdf, and /competition reports the requested competition information.

Written by the indexing model from the issue text.