Split KITT.Core project one per Bounded Context

[albx]

Actually the KITT.Core project contains all entities related to KITT (streamings, proposals, etc.).
Moving the project to .NET Aspire (see #109 ) and splitting each world in a separate bounded context (CMS, Proposals and others in the future) the KITT.Core project need to be splitted itself in order to become a class library per bounded context which contains all the "domain logic" related to the bounded context.

Up to now the BC identiefied are:

• Cms (Streamings and contents in general such as talks and maybe video in the future)
• Proposals
• (in the future) Media management