Add avatar saving functionality (without CDN support)

Cargo.toml

@@ -25,7 +25,7 @@ members = [
 
 [workspace.dependencies]
 rocket = { version = "0.5.1", features = [ "json" ] }
-actix-web = { version = "4" }
+actix-web = { version = "4", default-features = false, features = [ "macros", "compress-brotli", "compress-gzip", "compress-zstd"] }
 actix-files = "0.6"
 libfj = { version = "0.7.5", path = "../libfj" }
 log = "0.4"