Added option to select playback speed from a list of values

[frozenduck]

I had to move the speed selection option up because the screen did not fit all the values in the drop-down list, otherwise everything works fine.

[moisout]

Thanks a lot for this PR, I'll check it out as soon as i can

[moisout]

Other than the things I wrote above, it looks good to me!
If you want to, you can format the files with prettier using the config file in the repo, not required tho.

[frozenduck]

I fixed the styles and number parsing, probably should be fine now.

[moisout]

LGTM👍️, thank you!