backend: don't upload RPM packages to Pulp as artifacts

Fix pulp/pulp_rpm#3719

Instead of uploading RPM packages as artifacts in one API call, and
then creating a content from them in a separate call, we will now
create the content directly.

There are mutiple reasons to do so:

- One API call instead of two
- It fixes the issue with installing packages mentioned above
- @dkliban says there is an effort to not allow uploading artifacts on
  shared Pulp instances

There is only one disadvantage of doing this, we lose track of what
RPM packages belong to a specific Copr build ID. We will use labels
for this, once they are implemented.

See pulp/pulpcore#3338 (comment)

backend/copr_backend/pulp.py

@@ -151,28 +151,17 @@ def update_distribution(self, distribution, publication):
         }
         return requests.patch(url, json=data, **self.request_params)
 
-    def create_content(self, repository, artifact, relative_path):
+    def create_content(self, repository, path):
         """
         Create content for a given artifact
         https://docs.pulpproject.org/pulp_rpm/restapi.html#tag/Content:-Packages/operation/content_rpm_packages_create
         """
         url = self.url("api/v3/content/rpm/packages/")
-        data = {
-            "repository": repository,
-            "artifact": artifact,
-            "relative_path": relative_path,
-        }
-        return requests.post(url, json=data, **self.request_params)
-
-    def upload_artifact(self, path):
-        """
-        Create an artifact
-        https://docs.pulpproject.org/pulpcore/restapi.html#tag/Artifacts/operation/artifacts_create
-        """
         with open(path, "rb") as fp:
-            url = self.url("api/v3/artifacts/")
-            data = {"file": fp}
-            return requests.post(url, files=data, **self.request_params)
+            data = {"repository": repository}
+            files = {"file": fp}
+            return requests.post(
+                url, data=data, files=files, **self.request_params)
 
     def delete_repository(self, repository):
         """

backend/copr_backend/storage.py

@@ -161,18 +161,8 @@ def upload_build_results(self, chroot, results_dir, target_dir_name):
                     continue
 
                 path = os.path.join(root, name)
-                response = self.client.upload_artifact(path)
-                if not response.ok:
-                    self.log.error("Failed to upload %s to Pulp", path)
-                    continue
-
-                artifact = response.json()["pulp_href"]
-                relative_path = os.path.join(
-                    self.owner, self.project, target_dir_name)
-
                 repository = self._get_repository(chroot)
-                response = self.client.create_content(
-                    repository, artifact, relative_path)
+                response = self.client.create_content(repository, path)
 
                 if not response.ok:
                     self.log.error("Failed to create Pulp content for: %s, %s",