checking for admins should always be reloaded from disk

[xmonader]

Right now, a server running and I want to add an admin, I should go to the active running server shell and do it there and can't be done from any other shell. I think it's best if we always reload when checking the admins..

[xmonader]

@ashraffouda please add your suggestions here as well

[ashraffouda]

@ashraffouda please add your suggestions here as well
I suggest to make this change in redis like when updating that on disk it updates redis and read the admins from redis after that
also if it is possible to have this on the ui so the user can easily add admins