Remove duplicates of sample config files for the node

[bobbinth]

After merging #312, we will have sample config files (miden-node.toml and genesis.toml) stored in 2 different places (i.e., in node and in packaging directories). This is not a big deal, but I think ideally we should have a "single source of truth" for these. Assuming we want to do this, we have the following options:

1. Keep the only copies in the node directory. I think we'll need to update the packaging task to work with this.
2. Keep the only copies in the packaging directory. We may need to update our docker build scripts for this (and maybe something else?).
3. Put these files into some dedicated directory (e.g., config). We'll need to update both the Debian package task and docker build script.

I'm not sure what's the best approach here is - maybe option 3?

[bobbinth]

Closed by #353.