Provide default devfile for projects if not present
## Description
Context - https://gitlab.com/groups/gitlab-org/-/epics/14113#note_2013471216
In order to provide a zero-friction experience to users to be able to create a workspace, we should allow creating a workspace from a project which does not have a .devfile.yaml by defaulting its value to a simple devfile running a golden container image which has some of the most commonly used tools.
## Related Issues
- See [this internal comment thread](https://gitlab.com/gitlab-org/gitlab/-/issues/457993#note_2103906488) for a possible related requirement / acceptance criteria
epic