Add external dependencies CI/CD pipelines with SBOM generation

- Create external-dependencies directory structure with per-package pipelines
- Add DEPENDENCIES-INVENTORY.md with comprehensive dependency tracking
- Create ubuntu-26.04-build-container base image with all dependencies
- Add per-package Jenkinsfiles: log4qt, grantlee, googletest, postgresql, qt6-framework, kdreports
- Add SBOM generation script (generate-sbom.sh) for CycloneDX, SLSA v1.0, and license reports
- Integrate SBOM generation into all Jenkins pipelines
- Add external-dependencies/README.md with usage and security documentation
- Exclude proprietary license files (rti_license.dat) from git tracking

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Entire-Checkpoint: 01M6KNFNMSPW4SY4J4SQTTPVBP

external-dependencies/postgresql/Jenkinsfile

@@ -0,0 +1,95 @@
+pipeline {
+    agent any
+
+    environment {
+        PG_VERSION = '16'
+        HARBOR_REGISTRY = 'harbor.sl.defence-elec.de/proxydockerhub'
+        IMAGE_NAME = 'postgresql'
+        IMAGE_TAG = "${PG_VERSION}"
+    }
+
+    options {
+        timeout(time: 15, unit: 'MINUTES')
+        buildDiscarder(logRotator(numToKeepStr: '10'))
+    }
+
+    stages {
+        stage('Checkout') {
+            steps {
+                checkout scm
+            }
+        }
+
+        stage('Build PostgreSQL Container') {
+            steps {
+                script {
+                    dir('external-dependencies/postgresql') {
+                        sh """
+                            docker build \
+                              --build-arg PG_VERSION=${PG_VERSION} \
+                              -t ${HARBOR_REGISTRY}/${IMAGE_NAME}:${IMAGE_TAG} \
+                              .
+                        """
+                    }
+                }
+            }
+        }
+
+        stage('Verify PostgreSQL') {
+            steps {
+                script {
+                    sh """
+                        docker run --rm ${HARBOR_REGISTRY}/${IMAGE_NAME}:${IMAGE_TAG} bash -c '
+                          psql --version
+                        '
+                    """
+                }
+            }
+        }
+
+        stage('Generate SBOM') {
+            steps {
+                script {
+                    dir('external-dependencies/postgresql') {
+                        sh """
+                            mkdir -p sbom
+                            
+                            # Set environment variables for SBOM generation
+                            export GIT_URL="${env.GIT_URL}"
+                            export GIT_COMMIT="${env.GIT_COMMIT}"
+                            export BUILD_NUMBER="${env.BUILD_NUMBER}"
+                            export DOCKERFILE_PATH="external-dependencies/postgresql/Dockerfile"
+                            
+                            # Generate CycloneDX SBOM, SLSA provenance, and license report
+                            bash ../scripts/generate-sbom.sh postgresql ${PG_VERSION} ./sbom
+                        """
+                    }
+                }
+            }
+        }
+
+        stage('Push to Registry') {
+            steps {
+                script {
+                    withCredentials([usernamePassword(
+                        credentialsId: 'harbor-credentials',
+                        usernameVariable: 'HARBOR_USER',
+                        passwordVariable: 'HARBOR_PASSWORD'
+                    )]) {
+                        sh """
+                            echo ${HARBOR_PASSWORD} | docker login ${HARBOR_REGISTRY} -u ${HARBOR_USER} --password-stdin
+                            docker push ${HARBOR_REGISTRY}/${IMAGE_NAME}:${IMAGE_TAG}
+                            docker logout ${HARBOR_REGISTRY}
+                        """
+                    }
+                }
+            }
+        }
+    }
+
+    post {
+        always {
+            cleanWs()
+        }
+    }
+}