List of stuff in images

[abitrolly]

Is your feature request related to a problem? Please describe

Examnple: I'm always frustrated when I see markdownlint warnings in Gitpod, because I don't understand if it is only me who see them, because I install the extension at some point, or it is enabled for all users.

Describe the behaviour you'd like

See the list of all stuff that is included in base image.

Describe alternatives you've considered

I looked through Dockerfile, but I could not find any references to markdownlint.

[axonasif]

#958 might be related

[abitrolly]

Unless lists in #958 are compiled automatically, there is always a risk that for them to be outdated.