Escalate user privileges for root targeted dotfiles

[RaphGL]

Switching to root by doing sudo changes the assumed path of TUCKR_HOME to /root. So one has to do

TUCKR_HOME=$HOME/.config sudo tuckr a <group>

Tuckr should be able to escalate the user without this. Possibly manually setting and unsetting this variable when it escalates.

[krokosik]

I find the way tuckr handles root paths the most appealing and elegant to me out of the considered solution and it made me try it in the first place and this would make it perfect!