Wallet balances endpoint

[flannoo]

Would it be possible to implement an endpoint where we can retrieve all wallet balances at a certain snapshot height?

With the new implementation of incremental snapshots, there is no easy way anymore to query this information from the node API, so it would be nice to have that query available in the block explorer.

The result of the API endpoint could looks something like this:
{ "ordinal": 0, "balances": { "DAGXXXX": 1000000000000, "DAGYYYY": 2000000000000, "DAGZZZZ": 3000000000000 } }

Thx!