[FEATURE] Improved CMake Installation Support

[BestITUserEUW]

When integrating the Kinesis Video Producer library into a project, the current installation step includes the entire source directory, including .cpp files:

install(
  DIRECTORY ${KINESIS_VIDEO_PRODUCER_CPP_SRC}/src
  DESTINATION .)

Would it be possible to provide a proper installation process that installs only the necessary headers and compiled library for end-users?

This approach is already supported by other AWS C++ libraries, such as:

• https://github.com/aws/aws-iot-device-sdk-cpp-v2
• https://github.com/awslabs/aws-crt-cpp
• https://github.com/aws/aws-sdk-cpp

Currently, as a workaround, I have to build the Kinesis Video Producer library directly within my application, which I would prefer to avoid.