Add setting to use pywal Skip changing colors in terminals

[cwfryer]

Pywal has an option to skip setting the terminal colors. It accepts a boolean option in the pywal.sequence.send function

This PR adds that as a CLI flag --noterminal and also as a wpg.conf setting

[deviantfero]

hi, could you post a screenshot of the new settings UI?

[cwfryer]

Screenshot attached. It's an edited screenshot based on the current version of wpgtk.

[deviantfero]

sorry for taking so long to merge this :)