Introduce a script for updating Packit configs

The script provides 3 commands (see particular command's --help for more info):
1. download-configs - to download the configs of the repos that used Packit Service in the past year
2. list-affected - to list the projects affected by particular migration
3. migrate - to update the config and create PR

Related to #159
Related to packit/packit-service#1775

.gitignore

@@ -4,3 +4,5 @@ fedora-spec-files/rpm-specs
 fedora-spec-files/rpm-specs-latest.tar.xz
 fedora-spec-files/.ipynb_checkpoints
 fedora-spec-files/data.json
+
+automatic-config-updates/packit_configurations