Draft: Gitpod optimisations

What does this MR do and why?

⚠ This MR needs the following MRs merged first:

• !110975 (merged)
• gitlab-development-kit!2936 (closed)
• gitlab-development-kit!2937 (merged)

This MR updates the .gitpod.yml to:

• Do less work by pushing that logic into the Gitpod Docker image creation.
• Move most logic into the 'GDK' task because the bulk of the logic is GDK related.
• The 'GitLab' task now waits for the 'GDK' task and prints Thu 15 Dec 2022 07:58:49 AM UTC – Waiting for GDK to be configured.. to the user until ready.
• Every echo is now timestamped and sent to /workspace/startup.log.
• Improve readability by adding newlines where appropriate.

To test

https://gitpod.io/#https://gitlab.com/gitlab-org/gitlab/-/tree/ashmckenzie/tidy-up-gitpod-yml-2/

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.