introduce Username, Realm and Userid api types

and begin splitting up types.rs as it has grown quite large
already

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/api2/node/disks/zfs.rs

@@ -254,7 +254,7 @@ pub fn create_zpool(
 
     let to_stdout = if rpcenv.env_type() == RpcEnvironmentType::CLI { true } else { false };
 
-    let username = rpcenv.get_user().unwrap();
+    let userid: Userid = rpcenv.get_user().unwrap().parse()?;
 
     let add_datastore = add_datastore.unwrap_or(false);
 
@@ -314,7 +314,7 @@ pub fn create_zpool(
     }
 
      let upid_str = WorkerTask::new_thread(
-        "zfscreate", Some(name.clone()), &username.clone(), to_stdout, move |worker|
+        "zfscreate", Some(name.clone()), userid, to_stdout, move |worker|
         {
             worker.log(format!("create {:?} zpool '{}' on devices '{}'", raidlevel, name, devices_text));