Scoreboard Support and API

[lukeeey]

Originally created by RednedEpic at CloudburstMC/Nukkit#1420

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This brings in a scoreboard API (and eventually a finished system to interact with /scoreboard commands) to Cloudburst. For the time being, this PR will mostly only cover support for scoreboards (with an API to do so) that are the equivalent of that of what can be done in vanilla Bedrock itself, however, this may also include some additions that are slightly beyond the scope of vanilla Bedrock, such as adding support for multiple criteria and teams.

I also did what other parts of the codebase have done and split up the API and implementation for the scoreboards themselves. There are some parts of the code (such as the static builder methods in the API classes) which directly call on the impl classes. However when Cloudburst eventually does split up the API and implementation, adding in some sort of builder provider should be quite easy to do.

What's left to do:

• Scoreboard API
• /scoreboard command (working on) - in another PR
• Per-world scoreboards (for interacting with the scoreboard command) -in another PR
• (?) Team and multiple criteria support (?)

[lukeeey]

I've removed the scoreboard command that i was working on (ill add it back in a future PR) and simply left the API