Fix FileNotFoundError: [Errno 2] No such file or directory: 'python': 'python'

[phavekes]

If the host system has no /usr/bin/python, the task
TASK [stepup-ra : Put parameters.yml, samlstepupproviders(_parameters).yml and global_view_parameters.yml]

will fail with error message:
failed: [app.host.domain.tld] (item=parameters.yml) => {"ansible_loop_var": "item", "changed": false, "item": "parameters.yml", "msg": "FileNotFoundError: [Errno 2] No such file or directory: '/usr/bin/python': '/usr/bin/python'"}

A workaround is adding a symlink to python2, but it should be
corrected by detecting the correct location for the python2 interperter in filter_plugins/custom_plugins.py