Replace VSE effect strips with "Visual Effects Properties" (as with Grease Pencil) and Modifiers

I proposed a similar idea a couple of years ago, but back then I proposed to replace all effect strips with modifiers. However, I kind of like the way visual effects are done with the Grease Pencil, and I believe the VSE should work in a similar way. So: add a Visual Effects Properties tab and move all visual effects (glow and gaussian blur) there. (And while we're at it: add the other grease pencil visual effects to the list)

The non visual effects (Transform and Speed control) should be replaced with Modifiers, I think. (One could argue that the Transform effect should be left out, now that strips can be transformed in the Strip tab, but cascading transforms could lead to results that one transformation can not do. So either the Transform effect should stay, or the current transform tool should be extended to include raw matrix input).

It would make editing a lot easier, and make the VSE interface more consistent with the rest of Blender.