Add Github actions for automatic tests and building

[dl1com]

Achievable with vanilla Github Runner (low hanging fruits):

• Run clang-format
• Run Unit Tests
• Build Simulation Binaries
• Build Standalone Binaries for Target with gcc-linaro compiler

Will require a custom Github Runner because we need the Xilinx Vivado SDK:

• Build Standalone Binaries for Target with Xilinx gcc-arm-linux-gnueabi
• Build Firmware Image for Target

Also on custom runner because of workload and duration, perhaps only triggered with specific tags:

• Run Simulations and publish results, maybe even define a "fail" criteria? -> moved to #33

[dl1com]

Will require a custom Github Runner because we need the Xilinx Vivado SDK:

• Build Standalone Binaries for Target with Xilinx gcc-arm-linux-gnueabi
• Build Firmware Image for Target

Beware of using self-hosted runners in public repos and Pull Requests: https://github.community/t/self-hosted-runner-security-with-public-repositories/17860