feat(ui): revise image viewer

- Viewer only exists on Generation tab
- Viewer defaults to open
- When clicking the Control Layers tab on the left panel, close the viewer (i.e. open the CL editor)
- Do not switch to editor when adding layers (this is handled by clicking the Control Layers tab)
- Do not open viewer when single-clicking images in gallery
- _Do_ open viewer when _double_-clicking images in gallery
- Do not change viewer state when switching between app tabs (this no longer makes sense; the viewer only exists on generation tab)
- Change the button to a drop down menu that states what you are currently doing, e.g. Viewing vs Editing

invokeai/frontend/web/public/locales/en.json

@@ -142,9 +142,11 @@
         "blue": "Blue",
         "alpha": "Alpha",
         "selected": "Selected",
-        "viewer": "Viewer",
         "tab": "Tab",
-        "close": "Close"
+        "viewing": "Viewing",
+        "viewingDesc": "Review images in a large gallery view",
+        "editing": "Editing",
+        "editingDesc": "Edit on the Control Layers canvas"
     },
     "controlnet": {
         "controlAdapter_one": "Control Adapter",
@@ -365,10 +367,7 @@
         "bulkDownloadRequestFailed": "Problem Preparing Download",
         "bulkDownloadFailed": "Download Failed",
         "problemDeletingImages": "Problem Deleting Images",
-        "problemDeletingImagesDesc": "One or more images could not be deleted",
-        "switchTo": "Switch to {{ tab }} (Z)",
-        "openFloatingViewer": "Open Floating Viewer",
-        "closeFloatingViewer": "Close Floating Viewer"
+        "problemDeletingImagesDesc": "One or more images could not be deleted"
     },
     "hotkeys": {
         "searchHotkeys": "Search Hotkeys",