Fixed several issues in the documentation (links, deprecated API, etc.).

src/design/attitude-class-diagram.puml

src/design/available-propagators-class-diagram.puml

src/design/bodyshape-class-diagram.puml

src/design/celestial-bodies-class-diagram.puml

src/design/frames-class-diagram.puml

src/design/propagation-class-diagram.puml

src/site/markdown/architecture/attitudes.md

src/site/markdown/architecture/propagation.md

src/site/markdown/data/supported-data-types.md

src/site/markdown/index.md