Add the possibility to encrypt certain JSON fields

**Is your feature request related to a problem? Please describe.**
Currently, the JSON data for instance data and solution data are stored in plaintext. This poses a security risk if there is sensitive information, as anyone with access to the storage can read sensitive information.

**Describe the solution you'd like**
I want to enable encrypting the entire JSON for instance data and solution data, controlled by an environment variable. The encryption key will be securely fetched from a Google Cloud Storage bucket at runtime and used to encrypt and decrypt the JSON data.

**Describe alternatives you've considered**
- Hardcoding the encryption key in environment variables, which is less secure and harder to manage.
- Storing data without encryption, which risks exposure of sensitive information.

**Additional context**
Encrypting the full JSON will enhance data security and integrate seamlessly with Google Cloud key management.

Start by tracing where instance data and solution data JSON is stored and where the service reads its environment configuration. Then investigate the runtime Google Cloud Storage key retrieval path and define the encryption and decryption boundaries; done means both JSON payloads are protected when enabled while existing storage behavior remains understood.

Written by the indexing model from the issue text.