LanguageServerProvider should be able to pass initialization options to Language Server

### Description

While developing new plugin (Language Client for Apache Camel) I found out that I am not able to pass initialization options to my Language Server. I opened [discussion](https://github.com/apache/netbeans/discussions/5776) few days ago about this but I get no response.
Camel Language server uses this initialization options for passing user preferences, like custom components, different catalog providers and so. This abilities are important for my thesis solution, so I decided to try edit existing API. I was able to pass these options, but I don't feel it's good enough to open Pull Request. You can see my partial solution in my NetBeans fork in branch [initOptions](https://github.com/pospisilf/netbeans/tree/initOptions). [(Link to specific commit changes.)](https://github.com/pospisilf/netbeans/commit/82c725026ffd4434bf5016a6dd293d7e7d2f81d6)

### Use case/motivation

Developer should be able to use whole potential of Language Server Protocol with added feature to pass initialization options to server.

### Related issues

_No response_

### Are you willing to submit a pull request?

No

Start with the LanguageServerProvider API and the linked initOptions branch and commit to understand the proposed change; the discussion provides additional context on the missing initialization options. The work is done when a language-server client can pass initialization options through the provider to the server, with the API behavior validated by the relevant NetBeans tests.

Written by the indexing model from the issue text.