Stop using alternate package indexes or channels since the release to the official ones

As khiops-python library is released to PyPI and conda-forge, promote these official sources and use them

Author: Thierry RAMORASOAVINA

README.md

@@ -13,10 +13,28 @@ in two ways:
 
 ## Installation
 
+Using `conda`
 ```bash
-conda install -c conda-forge -c khiops khiops
+conda create -n khiops-env
+conda activate khiops-env
+conda install -c conda-forge khiops
 ```
-Other install methods are documented at the [Khiops website][khiops-install].
+
+Using `pip` under Linux (in a `bash` shell)
+```bash
+python -m venv khiops-venv
+source khiops-venv/bin/activate
+pip install -U khiops
+```
+
+Using `pip` under Windows (in a `powershell` shell)
+```shell
+python -m venv khiops-venv
+khiops-venv\Scripts\activate
+pip install -U khiops
+```
+
+Other installation methods are documented at the [Khiops website][khiops-install].
 
 ### Requirements
 - [Python][python] (>=3.8)

doc/index.rst

@@ -6,11 +6,30 @@ Welcome to the Khiops Python API documentation page.
 
 Installation
 ------------
-Khiops is better installed with `conda package manager <https://docs.conda.io/en/latest/>`_
+Khiops can be installed with `conda package manager <https://docs.conda.io/en/latest/>`_
 
-.. code-block:: shell
+.. code-block:: bash
 
-    conda install -c conda-forge -c khiops khiops
+    conda create -n khiops-env
+    conda activate khiops-env
+    conda install -c conda-forge khiops
+
+Alternatively, you can install in a virtual environment using `pip`,
+under Linux (in a `bash` shell) :
+
+.. code-block:: bash
+
+    python -m venv khiops-venv
+    source khiops-venv/bin/activate
+    pip install -U khiops
+
+under Windows (in a `powershell` shell) :
+
+.. code-block:: powershell
+
+    python -m venv khiops-venv
+    khiops-venv\Scripts\activate
+    pip install -U khiops
 
 More details and other install methods are documented at the `Khiops website
 <https://www.khiops.org/setup>`_.