Add justfile as a project workflow interface

[andreiltd]

I have been maintaining a justfile as a workflow interface for my recent work. This might be helpful for someone else, but feel free to close the PR otherwise.

This provide unified interface for most of the common jobs with a single line commands.

E.g just wpt-server will make all the steps necessary to spin up the wpt tests server. All the recipies are listed below.

    build target="" flags=""                       # Build specified target or all otherwise
    b target="" flags=""                           # alias for `build`
    clean                                          # Run clean target
    clean-all                                      # Remove build directory
    componentize script="" outfile="starling.wasm" # Componentize js script
    c script="" outfile="starling.wasm"            # alias for `componentize`
    default                                        # List all recipes
    format *ARGS                                   # Format code using clang-format. Use --fix to fix files inplace
    fmt *ARGS                                      # alias for `format`
    integration-test                               # Run integration test
    t                                              # alias for `integration-test`

    [wpt]
    wpt-build                                      # Build web platform test suite
    wpt-server                                     # Run wpt server
    wpt-setup                                      # Prepare WPT hosts
    wpt-test filter=""                             # Run web platform test suite
    w filter=""                                    # alias for `wpt-test`
    wpt-update                                     # Update web platform test expectations

The defaults can be overwritten like this:

just builddir=cmake-build-release flavour=release wpt-test # run wpt tests in release

Resolves #179.

[guybedford]

I personally always maintain a bunch of these scripts and would be very much for having some easier commands.

Would we want to document this?

[andreiltd]

I'm happy to add an entry to Readme if we can resolve the discussion here: #179 :)

[andreiltd]

Rendered Readme

[guybedford]

Just a couple of comments then this would be great to see.

[guybedford]

Will give this one a day here for any feedback from @tschneidereit, otherwise will land tomorrow.