Update FAQ

[IceflowRE]

As noted in this message the FAQ should be updated as they are a bit outdated.
This issue can can be used to collect all issues with it.

From my side especially why not conan is horrible outdated.

• Public federation vs private federation

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Related issues:

• Why not conan Public federation vs private federation #11684

[PhoebeHui]

@IceflowREm, sorry I forget to reopen the old issue, and thanks for reporting this issue again!

[strega-nil-ms]

Yeah, this is incredibly outdated; in my opinion the answer is to just nuke it. It is extremely outdated and misleading on both sides.