add documentation for cmake install

[staxfur]

We should add documentation on installing the library using cmake:

• install on linux as shared library
• use cpp-terminal as shared library on linux
• install cpp-terminal as shared library on windows
• using shared libraries on windows
  • place into shared include dir?
  • place next to the dll
  • static linking
  • other methods? Maybe visual studio stuff
• MacOS specific things?
• cross platform approach for managing cpp-terminal using cmake
  • git submodules
  • cmake managed
  • mamba?
  • other ways / package managers?

[ShalokShalom]

Currently, there is all the documentation about CMake missing:

https://github.com/jupyter-xeus/cpp-terminal/wiki/Adding-CPP-Terminal-to-your-ptoject

In the end, the docs recommend two approaches, which are both not covered.
The only option remains the highly complicated one, that is .. not recommended.

P.S: Also, you mention in this documentation, that the project consisted of two header files in 2021, and the README says it was just one.

Thanks a lot