feat: added FreeBSD support

to make use of it, create a FreeBSD VM with curl installed and install
rustup by default from rustup.rs, then run `cargo build -p sparse-05-server`

sparse-05/sparse-05-common/src/lib.rs

@@ -96,6 +96,7 @@ pub mod messages {
     pub enum OperatingSystem {
         Windows,
         Linux,
+        FreeBSD
     }
 
     #[derive(Serialize, Deserialize, Debug)]