Fledge v0.1.0

Runtimes for fledge build at v0.1.0, one per platform, each to build that platform's apps on a computer of that platform, with its SPDX SBOM and NOTICES; and, for Linux and Windows, the source the runtime's licenses ask for: its LGPL libraries', AppImage's runtime's, and NSIS's. What Fledge puts into each platform's app and installer, and what its licenses ask of you: doc/licensing.md at v0.1.0. What changed: CHANGELOG.md.