Added Support for Retriever Model Idea

[bshikin]

The idea is to create a "fake" conversation that mimics GPT model learning various language rules. The rules are defined under:

prompts:
...
   rules:
      - Remember these translation rules
      - \'Start()\' is equivalent to '_ready()'
      - \'Update()\' is equivalent to '_process(delta)'

Example LLM input looks like:

user: Remember these translation rules
assistant: Certainly! I have remembered this rule.
user: \'Start()\' is equivalent to '_ready()'
assistant: Certainly! I have remembered this rule.
user: \'Update()\' is equivalent to '_process(delta)'
...
user: Migrate this Unity C# code to GDScript class. Code to migrate:
using UnityEngine;
using UnityEngine.UI;

...

[bshikin]

Please note: this PR is on hold for a better implementation of the context lookup.

The idea is to load known samples into an in-memory DB and only attach ones that match the query best.

[bshikin]

No longer needed, https://github.com/ProjectUnifree/unifree/pull/47 is a more generic solution