Remove rpm operator-courier dependency and install it from pypi instead

When there is a new version of courier, the OCP Group F team has to
release it to PyPI, and then we pull it down and build a fedora rawhide
rpm out of it, and then we build a fedora 30+ rpm out of it and create
a bodhi update for that. Then, we wait ~24 hours for it to land in the
testing repo, so that we can build our container image and start
testing OMPS with the new version. This is a silly delay.

requirements-operator-courier.txt

@@ -0,0 +1,4 @@
+operator-courier == 2.1.8 --hash=sha256:b5482baeff662c1bcba5ec0a97e2f21132ee7a155580ab0ac3b886e1affd8396
+PyYAML == 5.3.1 --hash=sha256:b8eac752c5e14d3eca0e6dd9199cd627518cb5ec06add0de9d32baeee6fe645d
+validators == 0.17.1 --hash=sha256:898b6b8197fbc320daf25d3b32fa928fd25e225c33790cb58ed54b48aebe1858
+semver==2.10.2  --hash=sha256:21e80ca738975ed513cba859db0a0d2faca2380aef1962f48272ebf9a8a44bd4