The compare subcommand

[GrizzlT]

This subcommand should be able to compare two data versions (block data for now).

A few requirements:

• one directional comparison (i.e. from a version to another version)
• easy to read summary of the incompatibilities
• interactive menu for specifying compatibility fixes (although I think it's better if that was done in a different pr, feels like a separate topic to me)

First gonna figure out the ways block data can cause incompatibilities and list these here as well.

[GrizzlT]

First tests are promising. Forward compatibility is (as expected) quite well. Backwards compatibility seems a lot harder, evidently because of additions in later versions. Interesting, however, is that the number of individual block conflicts appears to be really low when compared to the amount of blocks. From 1.17.1 to 1.13, only 14 out of 590 blocks (excluding missing blocks) cannot be automatically matched between the two versions. I see this as a great confirmation this project can get somewhere real.

Next step would be specifying a format to list compatibility fixes in that would lead to maximum overlap between two versions.