Add 'all' recipe to justfile

[APonce911]

Include a new Just Recipe to run all other recipes.
Useful to run locally before opening the pull request for review.

to run:
just all

[tcharding]

This is kind of like just sane in rust-bitcoin

# Quick workspace sanity check.
@sane: lint
  cargo test --quiet --workspace --all-targets --no-default-features
  cargo test --quiet --workspace --all-targets --all-features

Note how we can define sane to call lint using the : syntax.

I'm not adverse to adding a just sane command here. I'm not super keen on a just all because I don't know when its useful to run everything eg updating the lock files is usually a planned action, not just on every PR.