docs: add langchain4j integration (mudler#1476)

* docs: add langchain4j integration

Signed-off-by: Ettore Di Giacinto <[email protected]>

* Update docs/content/integrations/langchain4j.md

Co-authored-by: LangChain4j <[email protected]>
Signed-off-by: lunamidori5 <[email protected]>

* Update langchain4j.md

Signed-off-by: lunamidori5 <[email protected]>

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Signed-off-by: Ettore Di Giacinto <[email protected]>
Signed-off-by: lunamidori5 <[email protected]>
Co-authored-by: lunamidori5 <[email protected]>
Co-authored-by: LangChain4j <[email protected]>