chore(changelog): add script to help creating correct changelog

`make -C CHANGELOG` to use it.

KAG-2527

CHANGELOG/Makefile

@@ -1,3 +1,8 @@
+.PHONY: new install_dependencies
+
+new:
+	./new.sh
+
 install_dependencies:
 	luarocks install penlight --local
 	luarocks install lyaml --local

CHANGELOG/new.sh

@@ -0,0 +1,79 @@
+#!/bin/bash
+set -e
+
+echo "What is this changelog for (kong, kong-ee, kong-manager)?"
+select component in kong kong-ee kong-manager; do
+    case $component in
+        kong|kong-ee|kong-manager) break;;
+        *) echo "Invalid option. Please select again.";;
+    esac
+done
+
+echo
+
+read -p "What is the title of the change? " title
+
+echo
+
+echo "What is the type of the change (feature, bugfix, dependency, deprecation, breaking_change, performance)?"
+select type in feature bugfix dependency deprecation breaking_change performance; do
+    case $type in
+        feature|bugfix|dependency|deprecation|breaking_change|performance) break;;
+        *) echo "Invalid option. Please select again.";;
+    esac
+done
+
+echo
+
+echo "What is the scope of the change (Core, Plugin, PDK, Admin API, Performance, Configuration, Clustering)?"
+select scope in Core Plugin PDK "Admin API" Performance Configuration Clustering; do
+    case $scope in
+        Core|Plugin|PDK|"Admin API"|Performance|Configuration|Clustering) break;;
+        *) echo "Invalid option. Please select again.";;
+    esac
+done
+
+echo
+
+read -p "What are the associated PRs? (comma-separated, without spaces e.g. 123,124,125) " pr_input
+IFS=',' read -ra prs <<< "$pr_input"
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+file_name="$SCRIPT_DIR/unreleased/$component/${prs[0]:-unknown}.yml"
+
+echo
+
+echo "New changelog will be created at $file_name"
+
+echo
+
+read -p "What are the associated Jira tickets? (comma-separated, without spaces e.g. FTI-123,FTI-124) " jira_input
+IFS=',' read -ra jiras <<< "$jira_input"
+
+echo
+
+read -p "What are the associated issues? (comma-separated, without spaces e.g. 123,124,125) " issue_input
+IFS=',' read -ra issues <<< "$issue_input"
+
+echo "message: $title" > $file_name
+echo "type: $type" >> $file_name
+echo "scope: $scope" >> $file_name
+echo "prs:" >> $file_name
+for pr in "${prs[@]}"; do
+    echo "  - $pr" >> $file_name
+done
+echo "jiras:" >> $file_name
+for jira in "${jiras[@]}"; do
+    echo "  - \"$jira\"" >> $file_name
+done
+echo "issues:" >> $file_name
+for issue in "${issues[@]}"; do
+    echo "  - $issue" >> $file_name
+done
+
+echo
+
+echo "Changelog file generated as $file_name:"
+echo "Be sure to \"git add\" and \"git commit\" this file"
+echo "================================================================"
+cat $file_name