interface: add page (#17622)

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

pages/cisco-ios/interface.md

@@ -0,0 +1,13 @@
+# interface
+
+> Manage interfaces.
+> Accessed in configuration mode.
+> More information: <https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/interface/command/ir-cr-book/ir-i1.html>.
+
+- Configure a VLAN:
+
+`interface vlan {{1}}`
+
+- Set an interface to be active or inactive (this is run inside the interface command):
+
+`{{no shutdown|shutdown}}`