feat: repository architecture for files crate w. added tests

Signed-off-by: izzy <me@insrt.uk>

crates/core/files/src/implementation/mod.rs

@@ -0,0 +1,7 @@
+mod encryption_impl;
+mod media_impl;
+mod s3_impl;
+
+pub use encryption_impl::EncryptionKey;
+pub use media_impl::MediaImpl;
+pub use s3_impl::S3Storage;