Merge branch 'protover-rust-impl_squashed'

Makefile.am

changes/ticket22840

configure.ac

src/common/compat_rust.c

src/common/compat_rust.h

src/common/include.am

src/or/include.am

src/or/main.c

src/or/protover.c

src/or/protover.h

src/or/protover_rust.c

src/rust/Cargo.lock

src/rust/Cargo.toml

src/rust/external/Cargo.toml

src/rust/external/external.rs

src/rust/external/lib.rs

src/rust/include.am

src/rust/protover/Cargo.toml

src/rust/protover/ffi.rs

src/rust/protover/lib.rs