Add timestamps to confirmed and spent block columns

[BrandtH22]

The wallet currently displays the confirmed and/or spent block height for coins/tokens, it would be much more user friendly to instead display the timestamp of the transaction block and have the block height (and potentially transaction ID) in a tooltip for the coin/token

[Rigidity]

Good point, the wallet protocol doesn't provide this timestamp data though, so I'm not sure what the best way to get it would be.

[Rigidity]

The wallet protocol doesn't have a message for this, but it turns out the peer protocol does (and this can be called by wallets too). You can request the block header for the spent and confirmed heights and get the timestamp out of the foliage block info. I'll make a queue to request all of the block timestamps for the coin records in the wallet.

[geraldneale]

Making progress with this. All elements of fix (except JS portions) have been individually tested, including new queue. Next step: to combine, test, get reviewed and add to a pull request.

[geraldneale]

see #342 for updates