Feature request: Add dialogs to show that GPU is being change and to notify user that unable to switch directly from Integrated to NVIDIA

[sudoker0]

One of the thing about switching GPU is that you need to update the initramfs, and that could take some time, so the user would benefit from having a popup or at least a notification that: Yes, the GPU is being changed, please wait for some times instead of just... not showing anything and leaving the user thinking that the extension isn't doing anything.

Also, since the envycontrol doesn't allow directly switching from Integrated to NVIDIA, you should show an popup or a notification explaining that you need to switch to Hybrid first instead of... not showing anything and immediately showing a dialog to restart.