♻️ Rework rules registration

This commit adds a rule registry as a central place to register new
rules. It will expose a Description and a factory to create a rule
object.

rules/registry.go

@@ -0,0 +1,34 @@
+// Copyright 2024 Florian Beisel
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rules
+
+type RuleFactoryFunc func() HostnameRule
+
+type RuleDescriptor struct {
+	Description string
+	Factory     RuleFactoryFunc
+}
+
+var RulesRegistry = map[string]RuleDescriptor{
+	"notebook": {
+		Description: "Generates hostnames for notebooks.",
+		Factory:     func() HostnameRule { return &NotebookRule{} },
+	},
+	"server": {
+		Description: "Generates hostnames for servers.",
+		Factory:     func() HostnameRule { return &ServerRule{} },
+	},
+	// ... other rules ...
+}