Revert "Base: App Circle sidebar (add support floating window)"

This reverts commit 4c1feeef66cb7ebceaf3410832890226da45cc27.
Revert "Base: implement Floating window multitasking"

This reverts commit d80f28e4f93fd6d0e7d2ec0c01d27acaeb3c15ac.
Revert "out with split view"

This reverts commit 24f7b1f6dda864a8531c2d1c5e27149ab0921a76.
Revert "[1/2] Base: implement App circle sidebar"

This reverts commit 7544d9d59b63080fba8627da9ca309c61ca05805.