git-delete-squashed-and-merghed-branches: support any default branch
git-delete-squashed-and-merghed-branches: support any default branch

This commit updates the command to use git origin-head to get
the repository's default branch, similar to previous commits
which did that for shell based commands.

While at it, add support to running the script without a dedicated token
(it works if user set up git ssh properly.

Signed-off-by: Tomer Arbel Eliyahu <b1429e76db16b5907079fac30288f68952a0f52a@intel.com>

unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands