new method of pack loading, assume data or data.btw in root to point to all other

docs/packaging.txt

@@ -0,0 +1,15 @@
+assets are distributed by packs, which can come in archived or folder form (for development purposes)
+
+one pack by the name of 'data' is always assumed to be present alongside game executable root,
+whether in folder /data/ or /data.btw file, where precedence is taking over /data/
+
+root 'data' should be used to point to other dependency packs in /packs/data.toml file
+
+---
+[[deps]]
+source = "../../common-data" # where does it come from, might be an url
+name = "common-data"         # should be globally unique
+---
+
+they're mounted to / in the virtual file system by default, if same files are present in multiple packs,
+only the one loaded first is visible