Add encryption to LLM provider keys before saving it

[ashrafchowdury]

Is your feature request related to a problem? Please describe.

Currently, the LLM provider keys are being saved directly to local storage without any encryption, storing keys without encryption poses significant security risks.

Describe the solution you'd like

To enhance the security of our application, we need to ensure that all LLM provider keys are encrypted before being saved to local storage. This will help protect sensitive information and prevent unauthorized access in case of a security breach.

[mmabrouk]

Outdated. We are now planning to have a vault in the backend to resolve this.