[200 SigmaUSD] Update registered scans and re-scan the wallet after UpdatePool command

[greenhat]

Discovered in #109 (comment)

Since we need to do this on every oracle after they receive a new config, I think we need to check if existing scans reference a changed token id/address/etc. and only then update the scanids.json and trigger a wallet re-scan.

[kettlebell]

I will work on this.

[greenhat]

The bounty is sent. Thank you!