POC Guardarian Fiat on/off-ramp integration

# Background

We are considering allowing integrating with [Guardarian](https://guardarian.com/), which is a fiat on/off ramp, similar to Changenow. The goal is to make it easier for anyone who does not have crypto at all to buy creator tokens, NFTs and JOY, and also to cash out to fiat more easily from profits or for creators. Integrating them into Atlas deeply can be done in many ways, but at the core of it being able to execute the ramp and seeing the status of past and ongoing transactions seems like a bare minimum. Lets leave aside how to integrate it into Atlas more deeply so users understand that the option exists and when to use it.

# Proposal

Review the API of their service, understand how it works and how we would integrate it technically, with some estimation on time and resources needed.

- API documentation: https://api-payments.guardarian.com/v1/api-docs
- Additional API Features: https://guardarian.notion.site/Documents-for-partner-integrations-a525d9d4147144a1b2f2c126dc1b33ae