[feature suggestion] Add 'git stash export', 'git stash import' commands to allow to backup stash externally

I work in a very large repository, but all of it except for my stashed 
items can be re-downloaded from the remote URL.


Stash though is much smaller in size and is especially valuable. Its 
loss would be very expensive.


Could you please consider adding 'git stash export', 'git stash import' 
commands so that in case of an accidental repository loss stash can be 
imported from the external backup?


Thanks,

Yuri