[WIP] Feature: Adding ppa support for apt_repository

This is a work in progress PR to add ppa url support to apt_repository.

Example:
```
apt_repository "php55" do
  uri 'ppa:easybib/php55'
  distribution node["lsb"]["codename"]
end
```
Todo: 
- [x] implement feature
- [ ] Figure out rubocop issues 
- [ ] Update Documentation