Separation of committing and manifest

[mpmxyz]

Hello there,
I was quite surprised that adding a mod involved directly adding an entry to a large JSON file.
Reason being that I was used to a more decentralized system with programs for a minecraft mod.
Of course that exact approach is not meeting the high security standards.

On the other hand I am not sure if multiple people editing the same file does perfectly scale with a higher rate of edits.
I can imagine having to resolve tiny but probably annoying conflicts when two or more pull requests for new mods are added at the same time.
Another advantage of a less monolithic approach would be that mod authors could setup CD pipelines that would automatically prepare a PR for a new version. (It is much easier to create a new file than it is to edit one.)

To ensure that the power over the data stays within the repository I suggest the following:

1. Every project gets its own directory.
2. Within each directory there is a main json file and auxiliary json files for each version.
3. As part of this repository's CI/CD pipeline the json files are individually checked for correctness and then combined to form the manifest.

Secondary advantages are that due to the CI/CD middle layer there are basically a lot of hooks where you can check semantic validity and styles in more detail. (#74)
Making the editing of mod entries file based may also ease the process of auxiliary tools. (#75)
The separate "playzones" should also prevent accidental changes to other mods.