DEV: Replace setup.py with requirements.txt - inttests should not be installed

requirements.txt

+linkahead
+pytest
\ No newline at end of file

setup.py

-from setuptools import setup, find_packages
-setup(
-    name="PyCaosDB Integration Tests",
-    version="0.1.0",
-    packages=find_packages(),
-    tests_require=["nose>=1.0", "python-dateutil>=2.8.1"],
-)