v1.2: Add `create_bundle` option (#6)

* Add `create_bundle`

This adds a new mode that collects all shared libraries used within a
coredump and bundles them together into a tarball.

* Add some documentation and `debug_plugin`

* Remove keys

* Need to do bundling inside of rootfs images

* use `raise` instead of calling random address

* Try to fix readarray problems

* Dont' save symlinks