uniform waveform zoom CO regardless of preferences.

[Swiftb0y]

Feature Description

As pointed out in #12872 and #12896, often controllers only have a single control to uniformly scale the waveforms. As such, current implementations for this feature need to either rely on the fact that the "synchronize zoom levels across a waveforms" setting is turned on (as in ##12872) or need explicit input from the user to workaround this shortcoming (see #12896). As such, it would make sense to have an explicit control that exactly models the way the waveform zoom functionality works on many controllers.

This would also be another candidate for the uniform CO pitched in #12109 (comment)
Also related: #12387