Use VCPKG to install boost, also on Linux

[sylvlecl]

This will allow us to easily select the boost version we want, independently from the OS.

In order to simplify things, this PR includes the following change

• use header version of boost test

Why currently, we use the dynamic link version. This implies to install boost test as a dynamic library, independently of other libraries. This is feasible with VCPKG with a custom "triplet". However, the use of this dynamic library has shown more issues than benefits:

• the actual benefits in size and build time are completely negligible
• the fact that we need the dynamic link version si hidden: if a user installs the static version, he will not understand why tests don't run. By using the header version, we ensure the tests will work in any case.