Move 3D Viewport and Sequencer OpenGL render operators into a "Render Preview" sub-menu. The goal is to make the operation more clear, and being able to add new entries to render the active scene or Sequencer scene (handy when using the new "Sync Scene"). This also reduces the length of the `View` menu which in some cases can get quite long. See PR for details and screenshots. Resolves #146302 Pull Request: https://projects.blender.org/blender/blender/pulls/146316