Modernize CMake module system

Current CMake module system of PCL does only show in summary, when a module is not build because of a dependency is missing, even it was set as ON.

Instead of this we could to it like VTK 9: Instead of a simple checkbox (ON, OFF), they have a enum with more states (e.g. ON, OFF, DEFAULT).

As this would make it easier to make sure every required component is compiled, I suggest to switch to a similar schema.

Example: Your have a job to automatically build the PCL - and this works fine. After updating an dependency, e.g. CUDA, you don't see the job doesn't build anymore the GPU module. Currently this build still will be started and a broken build will be deployed (as the GPU module is missing, which is required by another job). When you could define a module as required, CMake could throw an error and the job would detect this error.

Start by reviewing PCL's current CMake module summary behavior and compare it with the linked VTK 9 module-state design. Determine how states such as ON, OFF, and DEFAULT should represent missing dependencies, and how a required module should fail configuration. Done means the design is agreed and required components cannot silently disappear from a successful build.