envycontrol: add page (#9889)

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/linux/envycontrol.md

@@ -0,0 +1,28 @@
+# envycontrol
+
+> GPU switching utility for Nvidia Optimus laptops.
+> More information: <https://github.com/bayasdev/envycontrol>.
+
+- Switch between different GPU modes:
+
+`sudo envycontrol -s {{nvidia|integrated|hybrid}}`
+
+- Specify your display manager manually:
+
+`envycontrol --dm`
+
+- Check current GPU mode:
+
+`sudo envycontrol --query`
+
+- Reset settings:
+
+`sudo envycontrol --reset`
+
+- Display version:
+
+`envycontrol --version`
+
+- Display help:
+
+`envycontrol --help`