Add support for decrypting encrypted secrets in GA4K Remote Development module

MR: Pending

Description

As a developer, I want to be able to send encrypted secrets from rails to agent which can be decrypted by agent so that we can avoid decryption of secrets at rails(since it is an expensive operation).

Acceptance Criteria

TODO: Fill out (required)

• Decrypt a Kubernetes secret in place with a provided secret_key
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Technical Requirements

• Any time encrypted secrets are received by the agent, it can assume that the secret_key required to decrypt the data will also be provided in the same request.
• The agent is not required to persist the secret_key in Kubernetes.
• The Kubernetes Secret's data field will have key:value pairs. The key are plaintext data. The value is encoded version of encrypted data. The encryption method used will be aes-256-gcm. Encoding is required to pass the correct data across the wire.