Remove Qiskit.org links (#1087)

CONTRIBUTING.md

@@ -3,7 +3,7 @@
 First read the overall Qiskit project contribution guidelines. These are all
 included in the Qiskit documentation:
 
-https://qiskit.org/documentation/contributing_to_qiskit.html
+https://github.com/Qiskit/qiskit/blob/main/CONTRIBUTING.md
 
 While it's not all directly applicable since most of it is about the Qiskit
 project itself and rustworkx is an independent library developed in tandem

README.md

@@ -22,11 +22,11 @@ any Python application.
 ## Project history
 
 Rustworkx was originally called retworkx and was created initially to be
-a replacement for [qiskit](https://qiskit.org/)'s previous (and current)
+a replacement for [Qiskit](https://www.ibm.com/quantum/qiskit)'s previous (and current)
 NetworkX usage (hence the original name).  The project was originally started
 to build a faster directed graph to use as the underlying data structure for
 the DAG at the center of
-[qiskit-terra](https://github.com/Qiskit/qiskit-terra/)'s transpiler. However,
+[qiskit](https://github.com/Qiskit/qiskit/)'s transpiler. However,
 since it's initial introduction the project has grown substantially and now
 covers all applications that need to work with graphs which includes
 Qiskit.

docs/source/tutorial/dags.rst

@@ -125,11 +125,11 @@ Qiskit's Compiler
 -----------------
 
 Another application using directed acyclic graphs is the compiler in
-`Qiskit <https://qiskit.org>`__. Qiskit is an SDK for working with
+`Qiskit <https://www.ibm.com/quantum/qiskit>`__. Qiskit is an SDK for working with
 quantum computing. Qiskit's
-`compiler <https://qiskit.org/documentation/apidoc/transpiler.html>`__
+`compiler <https://docs.quantum.ibm.com/api/qiskit/transpiler>`__
 internally represents a quantum circuit as a
-`directed acyclic graph <https://qiskit.org/documentation/stubs/qiskit.dagcircuit.DAGCircuit.html>`__.
+`directed acyclic graph <https://docs.quantum.ibm.com/api/qiskit/qiskit.dagcircuit.DAGCircuit>`__.
 Rustworkx was originally started to accelerate the performance of the Qiskit
 compiler's use of directed acyclic graphs.