Separate precompiled libraries from core to shrink Repository size

[VojtechBartoska]

Current sdk folder is a few hundred megabytes, the repository itself is over 1.5GB. Adding new chips will only make this situation worse. This Issue is here to discuss possible ways to fix this problem for good.
Some initial ideas:

• Move sdk to external package/s, much like the toolchains or esptool.
• Archive the repository and start clean, not having sdk or tools as part of it.

[VojtechBartoska]

@me-no-dev Please help with the issue description, thanks.

[VojtechBartoska]

This will not be done for 3.0.0 release as it is not ready yet upstream.