Implement get, create and delete of login keys

[imadphp]

We should build a feature where we can add/delete/change/list all login keys. As far as I i’ve learned in the past several hours, we’ll have to use the CMD_LOGIN_KEYS command and send it regular requests. It seems that the API command for login keys is intended for something completely different. I’m currently working on this and will update this issue when I figure it out.