How to we display a users tokens for cirrus

[dangershony]

In this PR we have an api call to fetch token balance of a given address. https://github.com/block-core/blockcore-indexer/pull/131 However that means in the browser wallet the user will need to add in advance the contract address of a given token (sort of like how metamask does right now). Is that an acceptable approach? We could try to expose an endpoint that will try to discover the users tokens but it may be inaccurate, unless we attempt to precompute several tokens on each such call, and it sill may be inaccurate in some cases)