Implement role and user management enhancements

- Added MaxIpLimit to roles, allowing for the configuration of simultaneous IP limits for users.
- Updated role creation and update commands to include MaxIpLimit, ensuring proper handling in the application logic.
- Enhanced user management by introducing a DELETE endpoint for user accounts, with appropriate checks to prevent self-deletion.
- Updated documentation to reflect changes in role and user management, clarifying the new IP limit functionality and user deletion process.
- Adjusted related tests to cover new functionality and ensure robust validation of role and user management features.

backend/src/PnvPanel.Api/Endpoints/AdminUserEndpoints.cs

@@ -20,6 +20,7 @@ public static class AdminUserEndpoints
         admin.MapPatch("/users/{id:guid}/block", BlockUser).Produces(StatusCodes.Status204NoContent);
         admin.MapPatch("/users/{id:guid}/unblock", UnblockUser).Produces(StatusCodes.Status204NoContent);
         admin.MapPost("/users/{id:guid}/reset-password", ResetPassword).Produces(StatusCodes.Status204NoContent);
+        admin.MapDelete("/users/{id:guid}", DeleteUser).Produces(StatusCodes.Status204NoContent);
         admin.MapGet("/users/{id:guid}/configs", GetUserConfigs).Produces<IReadOnlyList<VpnConfigDto>>();
         admin.MapDelete("/configs/{id:guid}", ForceRevokeConfig).Produces(StatusCodes.Status204NoContent);
 
@@ -52,6 +53,12 @@ public static class AdminUserEndpoints
         return result.ToHttpResult();
     }
 
+    private static async Task<IResult> DeleteUser(Guid id, ISender sender, CancellationToken cancellationToken)
+    {
+        var result = await sender.Send(new DeleteUserCommand(id), cancellationToken);
+        return result.ToHttpResult();
+    }
+
     private static async Task<IResult> GetUserConfigs(Guid id, ISender sender, CancellationToken cancellationToken)
     {
         var result = await sender.Send(new GetUserConfigsQuery(id), cancellationToken);