change format for mod jars

- remove raw jars
- replace with modrinth.index.json
=> + save storage space and network bandwidth
=> - building is now more complicated

client/minecraft/config/immediatelyfast.json

@@ -1,6 +0,0 @@
-{
-  "experimental_disable_error_checking": true,
-  "experimental_disable_resource_pack_conflict_handling": false,
-  "experimental_sign_text_buffering": true,
-  "experimental_screen_batching": true
-}