Decide number of confirmations to wait for

[dholms]

Kraken requires 200 confirmations which takes about 100 minutes (https://support.kraken.com/hc/en-us/articles/203325283-Cryptocurrency-deposit-processing-times)

Some brief testing shows that waiting for 2 confirmations takes about 2 minutes.

Perhaps we could have 3 tiers of "confirmation level"

• not confirmed
• probably confirmed, you can start making storage deals but there's a chance it doesn't work
• completely confirmed