Release v0.0.4

Cleaning up the house 🏠

This version addresses a lot of the implementation complaints from the previous release and adds a few new features.
A brief overview:

• The help subcommand has been reworked to actually print usage docs for any subcommand passed in -- it will still display general usage docs if no argument is given. The new usage docs go quite in depth about the functionality of every subcommand with specifics that help in actually using mcsm. Try it out with mcsm help!
• The config subcommand now prints out all the the config values that will be used in both commands and server files instead of just what was parsed from the server.yaml. The structure's been updated, so a few keys will have changed. Now that config defaults are taken into account, the output can be used to understand everything as it will run in one go.
• Config validation was actually implemented now, so any modest gotcha's around some server types' config files such as build heights needing to be a multiple of 8 or game modes needing to have a specific spelling are checked for and reported on before launching the server during mcsm run. A validate subcommand has also been added to perform this static validation on-demand!
• The bedrock server type now uses a cached versions source, so install requests are way faster now -- at least as fast as any other current server types. 👀

There's going to be one more iteration of cleanups and self-care before further features are added. Hopefully, by release v0.0.6, we can settle on how mods and plugins are downloaded and configured 😁