CMake updates

I didn't know a release was imminent or I would have done a more thorough review! I missed a few things and added a few things.

- Fix spelling of monolithic build option
- Add install target for documentation.
- Make sure ALL libraries get installed when not building the monolithic library.
- Fix header files install broken by moving CMake config file to src.

Currently with the non-monolithic builds we're only setting a soversion on the SMESH library, should that be set for all of the libraries?