Move unsupported features under the "experimental" flag

[Patater]

It is hard to know what Mbed OS features or components are supported at the moment. We should move unsupported or deprecated features under a FEATURE_EXPERIMENTAL folder to communicate this. As FEATURE_EXPERIMENTAL is not enabled by default, we need to add this as a migration action for users of deprecated features in our Mbed OS release notes. Any Mbed OS examples using deprecated functionality should be archived, if they can't be updated to use only non-deprecated, non-experimental features.

[idea--list]

I get the idea and fully agree.
Would it add too much complexity to differentiate between which features are deprecated and what is being experimented on by having a DEPRECATED and a distinct FEATURE_EXPERIMENTAL folder?
This way things would not blend together and would be easier to follow.

[ladislas]

I agree with @idea--list -- separating both will make things even clearer. People who want to experiment new features and people who want to keep using old deprecated features are often not the same or not doing so in the same project.