Fix for gsol transfers and mint

[dankelleher]

The code here https://github.com/sunrise-stake/transaction-monitor/blob/master/index.js#L12 seems to be wrong.

To reiterate the requirement from the original ticket, the db needs to be populated with:

• gsol token mints (GSOL is a fungible SPL-token, not an NFT). They look like this
• gsol token transfers, that look like this

We have these already, but what we also need to do is recognise transfers that are part of CPIs, for example NFT purchases like this.

However, we should not be specific to any particular nft sale, as seems to be the mistake in the original code.

Also, this code needs to be flexible and easy to change. Different strategies should be easy to plug in. For example, we may want to exclude transfer CPIs triggered by a defi protocol like jupiter, or start putting nft purchases in a different table, for example. So the existing code should be refactored to allow this.