GRETL Runtime language server

This artifact contains unmodified Eclipse LSP4J 1.0.0 and LSP4J JSON-RPC 1.0.0.
Upstream source: https://github.com/eclipse-lsp4j/lsp4j/tree/v1.0.0
Upstream license: META-INF/LICENSE-LSP4J.txt (EPL-2.0 OR BSD-3-Clause / EDL-1.0).
Original about.html and upstream notices remain in the assembled archive.

The language server and protocol adapters are original GRETL Runtime code.
No implementation source was adopted from another GRETL stack for this module.
Other embedded libraries are the resolved, pinned Tooling-Core dependencies
(Apache Groovy, Jackson) and LSP4J's Gson dependency. Their upstream notices and
license resources are retained. Resolved versions are recorded by the build's
gretl-lsp/target/tooling-dependencies.json and the Maven metadata in this archive.
