Feat: Support custom playback speed

[RyanFoulds]

Addresses #889 by adding a second dialog with a SeekBar to choose a custom playback speed in the range 0.25x - 4x

Also adds localization to existing playback speed labels to support locations that use , to delimit decimals and . to delimit 1000s.
E.g. In Italian:

Notes

I've implemented this programmatically rather than using a declarative layout but tips/contributions for creating the dialog declaratively are appreciated.

[xFastz]

This is awesome and exactly what I was looking for! It was done 7 months ago?!

[RyanFoulds]

This is awesome and exactly what I was looking for! It was done 7 months ago?!

Glad you're happy with it, you can find a download of the GitHub-built APK for most phones here https://github.com/jarnedemeulemeester/findroid/actions/runs/16019472565/job/45192750459?pr=895#step:6:34

This build will not receive updates in line with the release schedule of the play-store version of the app and since it's not a real release, it's not likely to be as stable as one. Naturally the usual warnings apply, take care when installing apps from the internet.

Presumably, the maintainer might choose to merge this at some point, whereupon the above build will be obsolete and this functionality will become available in the next release version.

[xFastz]

Thank you so much for this! this is awesome. it looks quite different, but will be happy to try this out!