Fully version-pin Project Syn getting started guide

[simu]

This PR makes the following changes to the Project Syn getting started guide (https://syn.tools/syn/tutorials/getting-started.html)

• Make the Commodore and Lieutenant versions used by the guide page attributes
• Reformat some of the longer kubectl and curl commands to improve readability
• Pin the global Git repo (https://github.com/projectsyn/getting-started-commodore-defaults) to the Commodore version used in the getting started guide. This eliminates the need to update the getting started guide and the getting-started-commodore-defaults repo in lockstep. Conversely, updating the Commodore version in the getting started guide now requires creating a new tag on the getting-started-commodore-defaults repo.

This is in preparation for https://github.com/projectsyn/commodore/pull/284 and https://github.com/projectsyn/getting-started-commodore-defaults/pull/4

Checklist

• [x] Keep pull requests small so they can be easily reviewed.
• [x] Update the documentation.
• [x] Link this PR to related issues.