sound settings: Revive overamplication on input.

[SyberHexen]

disappeared at some point possibly in 520b4db

[anaximeno]

The switch for Overamplification in sound settings is only in the Output section, so from there it doesn't make sense to apply to both Output and Input.

[SyberHexen]

I agree this could be done better, but I didn't have much luck splitting the logic tied to the single overamplicfication_key to each tab.
Alternatively the overamplification toggle could be nested under sounds tab instead to look more in-place?

edit

Ideas:

1. Bring back the settings tab (or something similar like extras?) to have a single overamplification toggle controlling both output/input.
2. Split amplification per input / output having a toggle on each page (requires splitting the key 'allow-amplified-volume' in cinnamon-desktop and results in duplicated code.

[SyberHexen]

1. Bring back settings tab for single toggle idea here
2. This request splitting amplification per output/input page (which i'd rather squash into a single commit) assuming the key 'allow-amplified-volume' in cinnamon-desktop is also split as 'allow-amplified-out-volume' & 'allow-amplified-in-volume' keys.

While (1) still feels a bit out of place, (2) has sane placement and logic for users but is a larger change with likely unneeded code duplication.