[24095] Build: use GNUInstallDirs CMake module to create directory paths

[fedepell]

Description

Instead of defining manually certain install paths, use the standard (since 3.0) CMake module GNUInstallDirs to derive them. This is cross-platform and offers an automatic integration on distributions customizations (ie. when certain distribution system-wide define a specific place where to install stuff).

See also: https://cmake.org/cmake/help/v3.0/module/GNUInstallDirs.html

The goal is to make the build more modern and software easy to deploy in any distribution.

Contributor Checklist

• Commit messages follow the project guidelines.
• The code follows the style guidelines of this project.
• Changes are backport compatible: they do NOT break ABI nor change library core behavior.
• Changes are API compatible.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: CI pass and failing tests are unrelated with the changes.

[fedepell]

@richiware thanks for the review! I merged in the changes, look good to me! I've tried before not to change too much the original CMake script except what was directly related to the proposed change, but now it is even cleaner ;-)