chore: remove debian/fedora packaging

cubicweb-prometheus.spec

-# for el5, force use of python2.6
-%if 0%{?el5}
-%define python python26
-%define __python /usr/bin/python2.6
-%else
-%define python python
-%define __python /usr/bin/python
-%endif
-%{!?_python_sitelib: %define _python_sitelib %(%{__python} -c "from distutils.sysconfig import get_python_lib; print get_python_lib()")}
-
-Name:           cubicweb-prometheus
-Version:        0.1.0
-Release:        logilab.1%{?dist}
-Summary:        Exporting prometheus metrics
-Group:          Applications/Internet
-License:        LGPL
-Source0:        cubicweb-prometheus-%{version}.tar.gz
-
-BuildArch:      noarch
-BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-buildroot
-
-BuildRequires:  %{python} %{python}-setuptools
-Requires:       cubicweb >= 3.31.0
-Requires:       %{python}-six >= 1.4.0
-
-%description
-Exporting prometheus metrics
-
-%prep
-%setup -q -n cubicweb-prometheus-%{version}
-%if 0%{?el5}
-# change the python version in shebangs
-find . -name '*.py' -type f -print0 |  xargs -0 sed -i '1,3s;^#!.*python.*$;#! /usr/bin/python2.6;'
-%endif
-
-%install
-%{__python} setup.py --quiet install --no-compile --prefix=%{_prefix} --root="$RPM_BUILD_ROOT"
-
-%clean
-rm -rf $RPM_BUILD_ROOT
-
-%files
-%defattr(-, root, root)
-%{_python_sitelib}/*