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/bin/proxmox-backup-client.rs

@@ -184,7 +184,7 @@ pub fn complete_repository(_arg: &str, _param: &HashMap<String, String>) -> Vec<
     result
 }
 
-fn connect(server: &str, userid: &str) -> Result<HttpClient, Error> {
+fn connect(server: &str, userid: &Userid) -> Result<HttpClient, Error> {
 
     let fingerprint = std::env::var(ENV_VAR_PBS_FINGERPRINT).ok();