DNM PoC for gradual removal of Langchain

[jpodivin]

Description

The PR is not meant to be merged, it is only meant to demonstrate how we could gradually remove Langchain API from the code. The PromptTemplate can be replaced with simple replace call on a string object. The chain itself can be replaced with a bare LLM model.

This still involves Langchain during the model call, but it doesn't involve as many abstractions. Further improvement would be to replace LLM object from Langhchain with a simple wrapper for REST API calls.

Type of change

• Refactor
• New feature
• Bug fix
• CVE fix
• Optimization
• Documentation Update
• Configuration Update
• Bump-up dependent library
• Bump-up library or tool used for development (does not change the final image)
• CI configuration change
• Konflux configuration change

Related Tickets & Documents

• Related Issue #
• Closes #

Checklist before requesting a review

• I have performed a self-review of my code.
• PR has passed all pre-merge test jobs.
• If it is a core feature, I have added thorough tests.

Testing

• Please provide detailed steps to perform tests related to this code change.
• How were the fix/results from this change verified? Please provide relevant screenshots or results.

[tisnik]

@asamal4 FYI this is what we talked about (not anything we have to solve now, you know)