tests and documentation

...e/edit-item-page/item-metadata/item-metadata.component.ts

...elationship-list/edit-relationship-list.component.spec.ts

...dit-relationship-list/edit-relationship-list.component.ts

...e/item-relationships/item-relationships.component.spec.ts

...m-page/item-relationships/item-relationships.component.ts

src/app/core/auth/auth.service.spec.ts

src/app/core/auth/auth.service.ts

src/app/core/auth/server-auth.service.ts

src/app/core/cache/builders/build-decorators.ts

src/app/core/cache/builders/link.service.spec.ts

src/app/core/cache/builders/link.service.ts

src/app/core/cache/builders/remote-data-build.service.ts

src/app/core/data/entity-type.service.ts

src/app/core/data/relationship.service.spec.ts

src/app/core/data/relationship.service.ts

src/app/core/shared/item.model.ts

src/app/core/shared/search/search.service.ts

src/app/shared/mocks/mock-remote-data-build.service.ts

src/app/shared/utils/follow-link-config.model.ts