fix(enforcer.ts): fix deleteUser and improve deleteRole description

deleteUser now removes related grouping policies and normal policies related to user. Previously
just grouping policies were removed. Now deleteUser is more in line with deleteRole

fix #118

src/enforcer.ts

@@ -184,11 +184,14 @@ export class Enforcer extends ManagementEnforcer {
    * @return succeeds or not.
    */
   public async deleteUser(user: string): Promise<boolean> {
-    return this.removeFilteredGroupingPolicy(0, user);
+    const res1 = await this.removeFilteredGroupingPolicy(0, user);
+    const res2 = await this.removeFilteredPolicy(0, user);
+    return res1 || res2;
   }
 
   /**
    * deleteRole deletes a role.
+   * Returns false if the role does not exist (aka not affected).
    *
    * @param role the role.
    * @return succeeds or not.