initial commit

- login works
- basic documentation

src/keycloak/api.rs

@@ -0,0 +1,21 @@
+use std::fmt::Display;
+
+use serde::Deserialize;
+
+#[derive(Debug, Deserialize, thiserror::Error)]
+pub struct AuthError {
+    error: String,
+    error_description: Option<String>,
+}
+
+impl Display for AuthError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let error = &self.error;
+
+        if let Some(ref error_description) = self.error_description {
+            writeln!(f, "authentication type '{error}' with message '{error_description:?}'")
+        } else {
+            writeln!(f, "authentication type '{error}'")
+        }
+    }
+}