FDB should use dependency provider in CMake

[Xiaoge Su]

See:

https://cmake.org/cmake/help/latest/command/cmake_language.html#set-dependency-provider

[Xiaoge Su]

This may not make everyone happy but at least the benefit is that one could

• Either build using existing packages, e.g. build inside the Docker environment without a network connection
• Or build in a system without packages prebuilt, which allows one to download code and compile locally.