Allow the camera's zoom to be locked by a keybind
or a Gameplay setting. The zoom lock
behavior can be changed between Toggle
and Auto, where Auto only locks the camera
zoom while specific movement/combat inputs
are being pressed. (closes!1528)
A temporary fading notification is shown at the
top of the screen, informing the player of
the setting change (when the keybind is
used) or that the zoom is locked (when
the player might have forgotten the zoom
is locked, and is trying to zoom).
i18n strings are added for English and German,
but no other languages.
To implement the simplistic fading text, the
behavior was extracted into an impl
called `ChangeNotification`, where
reasons are quantified by `NotificationReason`.
