Add additional versions in the About tab

[Porkepix]

Checklist

• [x] This is a feature request.
• [x] I understand the difference between Streamlink and Streamlink Twitch GUI.
• [x] I tried solving my issue by reading the project's wiki first.
• [x] I have read the contribution guidelines und used the search function to find already existing threads.

Description

Add versions informations in the about tab.

Expected / Actual behavior

The about tab could show more versions informations, for example the streamlink version. It could even gather more informations like trying to get OS informations so that user can just copy and paste a block when filing issues following the current template.