Feature: allow kerbals to freeze themselfs

[ttr]

So currently, we need comms link (remote tech in my situation) or local control to freeze/thaw kerbals.
However I think that freezing should be allowed w/o any constrain. Logic behind this is that kerbals, when in cryo pod, they could start freeze process themself.

Thawing sill must require comms or someone else to trigger.

Obviously, this would affect peoples gameplay, so if this feature would be implemented, it could/should be controlled by settings switch.

thanks.