Add ability to query for balances by account and asset type

[aubrika]

Closes #2768

[conorsch]

@aubrika Thanks for tackling this on short notice. Still very interested in shipping this feature, but it's OK if it slips off 56: we can work with SL to use custom container versions, so whenever this lands, we'll have an associated hash; plus, all of the view.* protos are currently inaccessible to us in go until we resolve strangelove-ventures/interchaintest#658

[aubrika]

Broken CI is just due to proto changes, merging in as-is in advance of potential future feature requests