[Documentation] Adds json-ld to documentation

[simonneutert]

Hey Markus, I hope this is somewhat helpful :heart:

This pull request adds support for the JSON Lines (json-ld) format to the project. The documentation and command-line options have been updated to reflect this new format, and corresponding tests have been added to ensure correct reading and writing of json-ld data.

Support for JSON Lines (json-ld) format:

• Updated the README.md to mention that JSON input can optionally be line-delimited, and added json-ld to the list of supported input/output formats in the command-line options.
• Added tests for reading and writing the json-ld format in test/cq/formats_test.clj, I oriented myself on the json tests.