Create new branch for legacy code

legacy_from_xrve/lib/about.rs

legacy_from_xrve/lib/csr_handler.rs

legacy_from_xrve/lib/decode.rs

legacy_from_xrve/lib/fetch.rs

legacy_from_xrve/lib/instance.rs

legacy_from_xrve/lib/instruction_handler.rs

legacy_from_xrve/lib/io.rs

legacy_from_xrve/lib/lib.rs

legacy_from_xrve/lib/logging.rs

legacy_from_xrve/lib/pmmap.rs

legacy_from_xrve/lib/pmmap/memory_handler.rs

legacy_from_xrve/lib/pmmap/ram.rs

legacy_from_xrve/lib/standard_extensions.rs

legacy_from_xrve/lib/standard_extensions/i.rs

legacy_from_xrve/lib/state.rs

legacy_from_xrve/src/xrve-cli.rs

legacy_from_xrve/tests/unstringify.rs

legacy_from_xrve/tests/xrve/TODO add to this

legacy_from_xrve/tests/xrve_proc_macro.rs

legacy_from_xrve/xrve_proc_macro/Cargo.toml