ifmetric: add page (#10012)

* ifmetric: add page

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

pages/linux/ifmetric.md

@@ -0,0 +1,12 @@
+# ifmetric
+
+> An IPv4 route metrics manipulation tool.
+> More information: <https://0pointer.de/lennart/projects/ifmetric/>.
+
+- Set the priority of the specified network interface (a higher number indicates lower priority):
+
+`sudo ifmetric {{interface}} {{value}}`
+
+- Reset the priority of the specified network interface:
+
+`sudo ifmetric {{interface}} {{0}}`