Rustup 1.28.0: enhanced installation tool and website redesign

Rustup version 1.28.0 has been released, bringing a significant update to this essential tool for installing the powerful Rust programming language. Notably, Rustup will no longer automatically install the active toolchain if not present, and has added official support for new host platforms such as aarch64-pc-windows-msvc and loongarch64-unknown-linux-musl. This release also includes improvements like a cleaner output format for the 'rustup show' command, enhanced 'rustup doc' navigation, and more aliases for the 'rustup remove' command. Lastly, the official Rust website has undergone a redesign to better align with the Rust Project's branding.