Modernise the CMake approach

[joubs]

The purpose of this task is to take advantage of modern CMake features and refresh the CMake scripts used in the build process.

Here is a non-exhaustive list of considered options:

• Comply to the target/properties philosophy
• Export generation for visibility control
• This is not a feature but a connected notion: use of semantic versioning

This task also falls under the scope of improving the user experience of the library.