MultiSignature Contract - Access Control Extension

After a client lost funds due to a single owner wallet got hacked I decided to make a simple multi-signature implementation extending access control. I think it is a cheap and effective way to protect key contracts function execution like "Change Role" and "WIthdrawall" from malicious actors with access to one of the admins accounts.

This first version is quite simple as it gives "tickets" to execution without verifying the function inputs.

Feel free to contribute, review and criticize!