Started publishing side tooling not being python packages

[pthierry-ledger]

Some tools that are not packages has been published. These tools are mostly:

• very simple action files used for bare-metal cross-compilation related steps
• glue packages between python packages and build systems (only meson by now, to be extended to Cargo)
• CI related basic tooling, such as pre-made cross-files for meson. This last part aim to be replaced with SDK-based auto-generated cross-files