Create extensible REST API library

[luispfgarces]

The purpose is to create a new .NET class library (C#) that should be published as an additional Nuget package and should allow being added to an ASP.NET application HTTP pipeline, exposing new endpoints. The library should be able to:

• Be added as an additional configuration on the ASP.NET application startup file.
• Retrieve a RulesEngine instance from the service provider as the default behavior - application startup should not fail, but endpoints should fail when invoked.
• Allow defining, with custom logic, which RulesEngine instance is used by the REST API.
• Have an extensibility model that allows adding new endpoints - the library will have its' own endpoints, but library users should also be able to add their own endpoint implementations.
• Have the capacity to set which endpoints should be available - a default set of endpoints should be configured by the library, but it should be also possible to configure which endpoints will be available.