getTransaction improvements

[i5hi]

getTransactions has a few issues currently that are not immediately apparent:

• [ ] it should not assume all txs have 2 outputs - one recipient and one change

We currently check the output value and build the outAddrs List based on this.

Instead we should check the output.scriptPubkey, convert it to an address, search for that address in our address book and either update or add the address this way.

• [ ] it should not be the primary way change addresses are discovered, this should be done in address.dart using getInternalAddress

• [ ] it should check for self-transactions