Expand on debugging / backtraces via coredumpctl

https://developer.puri.sm/Librem5/Development_Environment/Boards/Troubleshooting/Debugging.html?highlight=coredumpctl helps to get started but just coredumpctl is not enough. You want matching debug packages (which requires adding a debug repository too) e.g. for phosh/phoc/squeekboard debugging see

Edited Dec 22, 2020 by Guido Gunther

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information