feat: cargo xtask

[EverlastingBugstopper]

Fixes #388

• Prep
  • Update npm dependencies
  • Install npm dependencies
  • Update npm package version
  • Run npm publish --dry-run
  • Update shell installer versions
  • Update error reference material
  • Copy the root CONTRIBUTING.md to docs/source/contributing.md
• Dist
  • Build release binary
  • Use strip to make binary size smaller
• Test
  • Make sure to accept a --target argument
  • Run cargo test --workspace --locked --target {target}
  • Run cargo test --workspace --locked --no-default-features --target {target}
  • Run cargo fmt --all -- --check
  • Run cargo clippy --all -- -D warnings and cargo clippy --all --no-default-features -- -D warnings
• Replace code in GitHub Actions with xtask
• Fix bug with auto-computing SHAs - programatically ensure they are computed or fail the release
• Update release docs to run cargo xtask prep
• Include info on using cargo xtask in CONTRIBUTING.md

[lrlna]

This is so good @EverlastingBugstopper !! Super happy with how this turned out.

[EverlastingBugstopper]

the changes to the CI process have been tested on my fork 😄 this is good to go

[lrlna]

This looks good! I'll let you do the honours of pressing the merge button :)