Add locale `sco` per community request
Add locale `sco` per community request

`sco` is for Scots, which is localized for Firefox and ready for Beta. There are links in the product that take users to mozilla.org.
alexgibson/bedrock,craigcook/bedrock,flodolo/bedrock,sylvestre/bedrock,mozilla/bedrock,mozilla/bedrock,sylvestre/bedrock,mozilla/bedrock,pascalchevrel/bedrock,craigcook/bedrock,pascalchevrel/bedrock,sylvestre/bedrock,alexgibson/bedrock,alexgibson/bedrock,flodolo/bedrock,pascalchevrel/bedrock,craigcook/bedrock,craigcook/bedrock,mozilla/bedrock,flodolo/bedrock,alexgibson/bedrock,flodolo/bedrock,pascalchevrel/bedrock,sylvestre/bedrock