raposza/tools: platform/raposza-bom/README.md

<!-- Copyright (c) 2026 bentzn --> <!-- SPDX-License-Identifier: Apache-2.0 --> # raposza-bom Bill of materials. Applications will import this to get a coherent set of platform versions without pinning each one. **NOT ACTIVE.** The module carries a pom with no `dependencyManagement` and no source, i