Suggestion: add derivation logs in the summary

[lucasew]

I, at least, have the habit of when a a PR settles I run this to check if that works on my machine is not happening but sometimes the build fails and it only posts if a package is failed or successfully built without any kind of logs.

My suggestion is to add the logs using summary/details so the logs are hidden by default but still acessible when the summary is posted.

But there are some concerns:

• How it will look in notification emails?
• Do GitHub have some kind of body limit when submitting a PR comment?
• Isn't it wiser to post the logs using a gist as ofborg sometimes do? (suggestion: all logs for a PR in the same gist using different files)

The link with related information about this summary/details thing: https://gist.github.com/scmx/eca72d44afee0113ceb0349dd54a84a2

[Mic92]

I am bit concerned that we abuse gist as a ci pastebin service. Unlike other pastebins they store logs forever. Just now it's only ofborg itself but this would multiple the number of logs done by individuals. What I could imagine is to store the last 25 lines per failed build in a summary and have a limit how many failed builds to include in this report.

[lucasew]

Seems fair