When animators want to key something in the viewport,
the code needs to know *which properties* should be keyed of that selected thing.
So far that was done with keying sets, and a pop-up that let's
you choose the keying set to use. You can get rid of the popup by
choosing a keying set ahead of time. But that is also not always desirable.
That pop-up is quite confusing and gives way too many options.
To simplify this process this PR adds a User Preference option to choose one or more of:
* Location
* Rotation
* Scale
* Rotation Mode
* Custom Properties
Now whenever the `I` key is pressed in the viewport,
and no keying set is enabled, it reads the preferences for which channels to insert.
# User Facing changes
* The popup will not be shown when pressing the hotkey,
but you can still explicitly use keying sets by going to the menu
* Which channels are keyed is defined by a User Preference setting under animation
* when a keying set is used explicitly, the User Preference settings are ignored
Part of #113278
Pull Request: https://projects.blender.org/blender/blender/pulls/113504
Cover the current behavior of keyframe insertion with unit tests,
so the changes planned in #113278 are less likely to break things.
Unit tests added:
InsertKeyTest
very basic test to ensure keying things by
name or with a keying set adds the right keys
VisualKeyingTest
check if visual keying produces the
correct keyframe values
CycleAwareKeyingTest
check if cycle aware keying remaps
the keyframes correctly and adds fcurve modifiers
Pull Request: https://projects.blender.org/blender/blender/pulls/114465
