Improve prebuild status messages including errors on the prebuild page

Problem to solve

Back in https://github.com/gitpod-io/gitpod/pull/8805, we improved the prebuild page (with logs and status) so that workspace instance status is used and prebuild status is reflected more accurately.

See also relevant issues:

• https://github.com/gitpod-io/gitpod/issues/5611
• https://github.com/gitpod-io/gitpod/issues/7384
• https://github.com/gitpod-io/gitpod/issues/8197

Re-posting a comment from @easyCZ in https://github.com/gitpod-io/gitpod/pull/8805#issuecomment-1081718220:

My intention for follow-up PRs is to clean-up the errors the server provides such that we treat them as "publicly facing errors" and include actionable feedback.

Some errors include also duplicate information that shows up on the status as well as inside the prebuild logs, see relevant comment in https://github.com/gitpod-io/gitpod/pull/8805#discussion_r837316450.

Proposal

To this extend, some error messages could be rephrased to look less scary or technical for users while providing full context of the error when possible. See relevant comments:

• https://github.com/gitpod-io/gitpod/pull/8805#discussion_r837317860
• https://github.com/gitpod-io/gitpod/pull/8805#discussion_r837319025
• https://github.com/gitpod-io/gitpod/pull/8805#discussion_r837320165

Start by reviewing PR #8805 and its referenced discussion comments, then compare the related issues #5611, #7384, and #8197 with the current prebuild page behavior. Done means the page presents less technical, actionable error messages with full context where possible and avoids duplicating information already shown in the logs or status.