Archive "non-unique" starters

[merelcht]

Description

With the introduction of the new spaceflights based starters and the new project creation flow, some of the older starters no longer offer unique examples that makes it worth maintaining them.

The starters that should be archived are:

• pandas-iris
• pyspark-iris
• pyspark
• standalone-datacatalog

Documentation

Need to update the docs to mention the new starters and remove mentions to archived starters.

[merelcht]

The starters are sub-directories in a repository, so they can't be archived individually. Github only does repo level archiving. I think we'll just have to delete them or "archive" them by simply adding "archived" in the readme.md.