This adds SPDX license headers to all source code files, following the
REUSE[1] specification. This does not include any asset files (such as
generated JSON files, or textures). While REUSE does support doing so
with ".license" files, for now we define these licences using the
.reuse/dep5 file.
[1]: https://reuse.software/
After several weeks of carefully arranging ribbons, we pull the string
and end up with, ... a bit of a messy bow. There were still some things
I'd missed.
- Split the mod into a common (vanilla-only) project and Forge-specific
project. This gives us room to add Fabric support later on.
- Split the project into main/client source sets. This is not currently
statically checked: we'll do that soon.
- Rename block/item/tile entities to use suffixes rather than prefixes.
