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/googletest/README.md

@@ -0,0 +1,35 @@
+# GoogleTest
+
+GoogleTest testing framework installation pipeline.
+
+## Version
+
+- **GoogleTest:** 1.15.2 (v1.15.2 tag)
+- **Repository:** https://github.com/google/googletest
+- **License:** BSD 3-Clause
+
+## Installation
+
+```bash
+git clone --depth 1 --branch v1.15.2 https://github.com/google/googletest.git /tmp/googletest
+cd /tmp/googletest
+mkdir build && cd build
+cmake -DCMAKE_BUILD_TYPE=Release \
+      -DCMAKE_INSTALL_PREFIX=/usr/local \
+      -DBUILD_SHARED_LIBS=ON \
+      ..
+cmake --build . -j$(nproc)
+cmake --install .
+```
+
+## Verification
+
+```bash
+pkg-config --modversion gtest
+```
+
+## SBOM
+
+- `sbom/googletest-1.15.2-sbom.json`
+- `sbom/googletest-1.15.2-provenance.json`
+- `sbom/googletest-1.15.2-licenses.md`