Introduce bash completions for kubecfg

completions only work for list, get, create, delete.
I'll update to use declare -F, but this one mostly kinda works.  I did test it.  It's just not as nice as the built in.  And if some function was counting on the built in, but it isn't there, all the better ours got loaded, since now they have at least some small chance of kinda working instead of it bombing...