Add Redpanda Secrets Store as third-party sync provider

[ptrtht]

Overview
Integrate Infisical with the Redpanda Secrets Store to allow automated syncing of sensitive configurations.

Description
Redpanda's native secret store is increasingly used for managing sensitive configurations in Redpanda Connect pipelines and managed connectors. Currently, these must be updated manually; a native Infisical sync provider would allow teams to manage these secrets centrally and push updates automatically.

Possible Solution
Implement a sync provider that utilizes the Redpanda Data Plane API to manage secrets.

• Target Endpoint: POST /v1/secrets
• Reference: Redpanda Create Secret API Documentation