Make the Rust implementation the only one: crate at the root, Go tree removed

src/lib.rs

@@ -0,0 +1,19 @@
+//! mapsize: interactive terminal disk usage analyser (Rust port).
+
+pub mod app;
+pub mod brand;
+pub mod cancel;
+pub mod config;
+pub mod duplicate;
+pub mod export;
+pub mod filter;
+pub mod inventory;
+pub mod platform;
+pub mod scan;
+pub mod snapshot;
+pub mod textutil;
+pub mod treemap;
+pub mod tui;
+
+/// Boxed error used across mode boundaries.
+pub type Error = Box<dyn std::error::Error + Send + Sync>;