Adjust 2D select/move/rotate/scale shortcuts to match 3D

[hakro]

This PR changes the Select/Move/Rotate/Scale shortcuts of the 2D editor to use Physical keys, so that non-QWERTY layout users can enjoy having those keys adjacent to each other.

As it turns out, it was already done for the 3D Editor (the true flag here : https://github.com/godotengine/godot/blob/master/editor/plugins/node_3d_editor_plugin.cpp#L9123)

I've also changed the Ruler shortcut to M, since that's how it's defined in 3D, so they now match each other, and since R is needed for Scale

[Mickeon]

See also the related discussion about physical events.

Tread carefully. Changing the default for the Ruler will most certainly screw up with the muscle memory of a lot of users. Modifying them all to be physical keys is objectively good, though.

[hakro]

Tread carefully. Changing the default for the Ruler will most certainly screw up with the muscle memory of a lot of users. Modifying them all to be physical keys is objectively good, though.

Right, but I think it makes more sense to have the same default shortcut for the same action in both 2D and 3D.