feat(apps): add git-push and deploy scripts for darwin and nixos

[steveej]

instead of rsync'ing the flake to the machine, the workflow will be to push the desired repository state to host-specific branches from which they can subsequently be deployed.

fixes #68.

• store self.sourceInfo somewhere on the machines

demo of how to read the source revision from the machine itself:

steveej@sj-bm-hostkey0 ✓ ~/src/holo/holochain-infra 🐚 deploy-from-github ⚡
$ (
  set -xE
  git diff --exit-code HEAD $(nix run .\#ssh-macos-02 "cat /etc/nix/sourceInfo.json" | jq --raw-output '.rev')
  echo deployed from HEAD
)
+-zsh:19> nix run '.#ssh-macos-02' 'cat /etc/nix/sourceInfo.json'
+-zsh:19> jq --raw-output .rev
+ ssh administrator@hydra-minion-2.holo.host cat /etc/nix/sourceInfo.json
+-zsh:19> git diff --exit-code HEAD d49d95a4c50ce49c87957d1d3f7bb1e3a70efa45
+-zsh:20> echo deployed from HEAD
deployed from HEAD

another demo:

$ jq . <(nix run .\#ssh-sbd-0_main_infra_holo_host "cat /etc/nix/sourceInfo.json")
+ ssh root@65.108.241.120 cat /etc/nix/sourceInfo.json
{
  "lastModified": 1716839508,
  "lastModifiedDate": "20240527195148",
  "narHash": "sha256-otiepXy7lVOBHXJFhp2J4CkKxzzOUuLMmDOFOio+jgc=",
  "rev": "b5706e0d43845f512589784c3e3a9dd69dc1a300",
  "shortRev": "b5706e0"
}

[steveej]

if the outPath attribute isn't removed the file would only contain the outPath i.e. nix-store path of the sources, which isn't helpful in this use-case.

[steveej]

this will be a text file that contains the path to the sources stored underneath /nix/store/...