move cameraZoom{In,Out} key bindings to a 'General View Controls' section
add English translation token for 'General View Controls'
declare key bindings for all the SectorView controls
add English translation tokens for all new Sector View key bindings
hook up all SectorView key bindings
ignore modifiers in KeyBinding::Matches if the binding doesn't use them

This matches the behaviour of KeyBinding::IsActive(), which only checks
the state of modifier keys if the binding itself requires at least one
modifier.