PlaybackSpeed: Add option to remember the last playback speed values

As on the Android application, we could add an option to allow users to save the last playback speed values (including the audio and subtitles delay as well).

changed milestone to %3.5.0

added Feature Player labels

assigned to @diogo.simao-marques

I feel like this is similar to #1739, no?

Yes.

marked this issue as a duplicate of #1739

closed

marked this issue as related to #1739