New protocol: Implement mod gathering

[lionkor]

The server needs to collect all mods (.zip files) from the $RESOURCE_FOLDER/Client folder.

Acceptance criteria

• [ ] Send list of mods in a special format to the backend in heartbeats (see existing code in THeartbeat).
• [ ] Each mod entry needs to also store: Hash of the mod, algorithm used to hash the mod (must currently be SHA256), file size, file name (separate from file location), and whether the mod is optional (always false). Also needs to store the method of getting the mod, currently that is "direct" (make an enum).
• [ ] Add it so that support for possibly hot-reloading mods (update hash, size), and adding mods on the fly could be done.
• [ ] Optional: Check that the mod is not empty, warn on empty folders or other files in the folder that are not .zip files.

[my-name-is-samael]

bump ! I would love to have mod adding on the fly ❤️

I posted an issue on BeamMP but it is more relevant in here => https://github.com/BeamMP/BeamMP/issues/577

TLDR: I want to add programmatically modded maps to switch map ingame (manually or with vote), but I don't want players to download EVERY maps on their first connection (can be too heavy). If changing map without reconnecting players would be tough (and I understand it would be), having client mods change on the fly would be awesome