cmake : handling bitpit external dependencies in MSVC project context

[roccoarpa]

Define a way to retrieve bitpit external dependencies as native built MSVC libraries. Actual deps are :

1. libxml2/rapidjson
2. lapack suite
3. petsc
4. boost (required by unit tests and/or as alternative to provide xml2/json support throug rapidxml/rapidjson)
5. mpi

Proposed idea: make use of nuget CLI (https://www.nuget.org/) for 1) to 4)
mpi is already available through the MS official tool msmpi (https://docs.microsoft.com/en-us/message-passing-interface/microsoft-mpi).