Duplicate Checking of Addins

With the new functionality that is provided by AddinDiscoverer to update and maintain the YAML files on the Cake Website, I think we have to start thinking about detecting duplicate addins.

For example, we have this:

https://www.nuget.org/packages/Cake.Aws.ElasticBeanstalk/

and this:

https://www.nuget.org/packages/Cake.Aws.ElasticBeanstalk.Dev/1.3.4-Dev

The second is clearly a duplicate of the first, and as such, I don't think it should be included. Ideally, this would be flagged, with an action for someone to follow up to try to figure out what is going on.

Start by reading AddinDiscoverer’s functionality for updating and maintaining the Cake Website YAML files, then trace how NuGet addins such as Cake.Aws.ElasticBeanstalk are represented. Define how the two example packages should be recognized as duplicates and how that condition should be flagged for follow-up; the work is done when duplicate addins are identified without excluding distinct packages.

Written by the indexing model from the issue text.