Mocking library for unit tests

[sylvlecl]

Description

Some unit tests would benefit from using a mocking library, instead of hand-written mocks.

In particular, the UT introduced in pull request https://github.com/AntaresSimulatorTeam/Antares_Simulator/pull/1716 would be written more easily with that.

Solution

A natural candidate for this is google mock. Its usage will require to update the CI and documentation with that new dependency.