Share driver libtraries among projects

[ttzeng]

The default option in STM32Cube is to copy all the library files into the generated projects, which casues same driver files were checked in to multiple projects. It would be effective to share libraries among projects and keep them aware from user git repos.

There was a discussion in the community forum on this topic, and according to this overview, STM32Cube is the comprehensive embedded software platform supporting overall STM32 products portfolio in two publication models: by MCU Package, or by MCU components:

• The MCU Package: a unique repo per STM32 MCU series containing the different components of a STM32 MCU firmware (Drivers, Middleware, Utilities, Examples).
• The MCU components: each component of a STM32 MCU firmware (Drivers, Middleware, Utilities) is published in a dedicated repo.