ip-maddress: 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):

[Managor]

I wanted to commit this now before I forget. I'll test the commands later

[Managor]

I was not able to get the join and leave commands to work. They only work for physical addresses and when I tried to use it to leave, the command complained about ioctl: No such file or directory

[Managor]

I got it working. The add and delete commands work for static addresses only. They do not affect multicast groups that were joined by a program on the system.

[spageektti]

Thanks