interface: add page

[Managor]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[TheRealGabHas]

LGTM.
Maybe we could add an example for the network interface as well (FastEthernet, GigabitEthernet, Serial...)

[Managor]

I want to get these starting point pages out based on what I've needed. You can add more once that's done.

[tldr-bot]

The build for this PR failed with the following error(s):

pages/cisco-ios/interface.md:11: TLDR102 Example description probably not properly annotated

Please fix the error(s) and push again.