Track solanart bid purchase (Plus other various update)

[kryptoj]

A bunch of update going into this PR:

• Fixed buyer address tracking, previous it wasn't accurate for bidding purchase
• Add bidding purchase tracking for solanart purchases
• Updated discord message to show purchase via bidding (See screenshot below)
• Updated solanart marketplace external link
• Updated debug endpoint to test notification on a specific signature One can now preview a notification locally on a given signature and channelID

  http://localhost:4000/test-sale-tx?signature=TX_SIGNATURE&channelId=DISCORD_CHANNEL_ID
  e.g.
  http://localhost:4000/test-sale-tx?signature=4PJ7X1ZCEj68n2HXfVx48jGnqgu9rWAxquVihpNvDizbZ5V5vUHViz2N54HHMUiBvKtx7mbmYAQ4unURg9YEgLM6&channelId=893632559001530394