- Notify about generating SSH config in the post-merge git hook.

- Added Documents/bin directory for scripts, moved renew-certs,
train-wifi and dma-clean (wasn't commited before) there.
- Made gen-ssh-config a script (in Documents/bin) instead of a shell
alias. Call said script in the post-merge git hook (instead of sourcing
bashrc which currently just exits if not running interactively which I
like to keep doing). Added said scripts to pre-commit.