Summary:
Moving our internal IP/Mac address libraries to folly/

Facebook:
We want to get rid of common/ dependencies in Mcrouter since we're going to open source it. Also looking at the original commit, seems like it's been the intention all along, so I just did it.

I tried to keep dependencies intact as much as possible. Changing projects to use this directly should be in separate diffs.

Test Plan:
Run folly/network and common/network unit tests.

Generate the list of targets with:

```
fbgs /$FILE.h | cut -f1 -d: | xargs -L1 dirname | cut -f2- -d/ | sort | uniq
```

Then fbconfig + fbmake. Will fix contbuild failures.

Revert Plan:

Reviewed By: simpkins@fb.com

FB internal diff: D1261089