Replace screenshots with transcripts

[lauft]

The screenshots in the documentation should be replaced with transcripts.

Those could be updated easier and do not have problems with scaling.

In this context one should investigate whether Hugo's highlighting allows to use shell escape characters for coloring and formatting.

[lauft]

https://timewarrior.net/docs/tutorial/ has been transcribed.

The following pages still contain screenshots:

• https://timewarrior.net/docs/summary/
• https://timewarrior.net/docs/corrections/
• https://timewarrior.net/docs/charts/
• https://timewarrior.net/docs/taskwarrior/
• https://timewarrior.net/docs/diagnostics/

Especially with chart displays it is important to find a solution to display text and background color