Create a langchain4j-core module

[lburgazzoli]

Description

Target

• [ ] I checked that the commit is targeting the correct branch (note that Camel 3 uses camel-3.x, whereas Camel 4 uses the main branch)

Tracking

• [ ] If this is a large change, bug fix, or code improvement, I checked there is a JIRA issue filed for the change (usually before you start working on it).

Apache Camel coding standards and style

• [ ] I checked that each commit in the pull request has a meaningful subject line and body.

• [ ] I have run mvn clean install -DskipTests locally and I have committed all auto-generated changes