Note banner in README file (#1790)

Add a banner with some context for the archiving.

Fix #1793

README.md

@@ -1,4 +1,9 @@
-![Image](https://raw.githubusercontent.com/Qiskit/qiskit-metapackage/master/images/qiskit_header.png)
+# Qiskit Metapackage (_ARCHIVED_)
+
+
+| ⚠️ NOTE                               | 
+|------------------------------------------|
+| Since August 2023, this repository is archived as all the  `qiskit` PyPI metapackage infrastructure and documentation was moved to [Qiskit/qiskit](https://github.com/Qiskit/qiskit) (formally [Qiskit/qiskit-terra](https://github.com/Qiskit/qiskit-terra)). See [RFC0011 for details](https://github.com/Qiskit/RFCs/blob/master/0011-repo-rename.md).|
 
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