Add relocation statement to readme

[alaimo]

Adjust the readme to reflect that active development of metacontroller has moved.

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[alaimo]

/cc @grzesuav @AmitKumarDas @fedebongio

[fedebongio]

/lgtm

[fedebongio]

We are archiving this repo, and for that purpose I'm merging the last PR with the updated new location for Metacontroller in the future.