feat: add ConnectionAddress type and Connectable traits

mavlink-core/src/async_connection/direct_serial.rs

mavlink-core/src/async_connection/file.rs

mavlink-core/src/async_connection/mod.rs

mavlink-core/src/async_connection/tcp.rs

mavlink-core/src/async_connection/udp.rs

mavlink-core/src/connectable.rs

mavlink-core/src/connection/direct_serial.rs

mavlink-core/src/connection/file.rs

mavlink-core/src/connection/mod.rs

mavlink-core/src/connection/tcp.rs

mavlink-core/src/connection/udp.rs

mavlink-core/src/lib.rs

mavlink/tests/parse_test.rs