Add Intel channel for installing wheels (#2098)

Author: ekomarova

README.md

@@ -41,7 +41,7 @@ python scripts/build_locally.py
 ## Install Wheel Package via pip
 Install DPNP
 ```cmd
-python -m pip install dpnp
+python -m pip install --index-url https://software.repos.intel.com/python/pypi dpnp
 ```
 
 Set path to Performance Libraries in case of using venv or system Python:

doc/quick_start_guide.rst

@@ -44,7 +44,7 @@ You will need one of the commands below:
 
 * Conda: ``conda install dpnp -c https://software.repos.intel.com/python/conda/ -c conda-forge``
 
-* Pip: ``python -m pip install dpnp``
+* Pip: ``python -m pip install --index-url https://software.repos.intel.com/python/pypi dpnp``
 
 These commands install dpnp package along with its dependencies, including
 ``dpctl`` package with `Data Parallel Control Library`_ and all required