Determine terminology to use

[ssbarnea]

When it comes to set of actions and group of actions that are executed by most build tools and CI/CD systems there is a great variance in terminology, one that often causes confusions for users. I want to pick good names while mk is still in research phase, so we do not repeat others mistakes.

• Jenkins has jobs > steps
• GHA has workflows > jobs > steps
• Tox has environments > commands
• NPM/yarn have scripts
• Makefile has targets

It should also be noted that we use Click/Typer which means that we already have a meaning for command, so a good reason to avoid using the term to define something else.

As of today the Runner class does discover actions exposed by tools mentioned above. These are translated into cli commands but we can rename them at any time.