feat: add static token issuer

Signed-off-by: rtriesscheijn <rtriesscheijn@bol.com>

plugins/auth-backend/config.d.ts

@@ -43,7 +43,7 @@ export interface Config {
 
     /** To control how to store JWK data in auth-backend */
     keyStore?: {
-      provider?: 'database' | 'memory' | 'firestore';
+      provider?: 'database' | 'memory' | 'firestore' | 'static';
       firestore?: {
         /** The host to connect to */
         host?: string;
@@ -65,6 +65,21 @@ export interface Config {
         /** Timeout used for database operations. Defaults to 10000ms */
         timeout?: number;
       };
+      static?: {
+        /** Must be declared at least once and the first one will be used for signing */
+        keys: Array<{
+          /** Path to the public key file in the SPKI format */
+          publicKeyFile: string;
+          /** Path to the matching private key file in the PKCS#8 format */
+          privateKeyFile: string;
+          /** id to uniquely identify this key within the JWK set */
+          keyId: string;
+          /** JWS "alg" (Algorithm) Header Parameter value. Defaults to ES256.
+           * Must match the algorithm used to generate the keys in the provided files
+           */
+          algorithm?: string;
+        }>;
+      };
     };
 
     /**