A plugin can now create a "Plugin" struct with Rust strings. The
`into_raw` method converts it to a raw pointer suitable for returning
during plugin registration.
Mostly a copy of Suricata core's logging wrappers into the ffi crate.
These are not yet used by Suricata-core as they do require the
Suricata library to be available, which is not the case with tests. And
the `cfg(test)` parameter is not passed through to sub-crates.
However, this does allow a plugin (or library) to call the logging
macros without depending on the "suricata" crate.
Ticket: #7666
This crate is for Rust wrappers around the -sys crate which includes
only raw bindings. This is the place to add nice wrappers around those
bindings, however it should remain clear of dependencies on the main
Suricata core crates.
Ticket: #7666