Make CMake targets more modular to reduce required dependencies

[RFRIEDM-Trimble]

As a user of this library, I want to just use a few parts of the library for things like J1939/Transport, but I am required to have a bunch of other dependencies to compile such as libgtest-dev protobuf-compiler libprotobuf-dev libncurses-dev libwebsockets jsoncpp

For example, if I just want transport, I should be able to build transport, with minimal requirements.

cmake -S . -B build && cmake --build build --target transport