Add and hide custom tokens

IIUC, currently all tokens are shown in the interface.

If the user receives a bunch of spam tokens, they should be able to hide them.

The other approach would be to do something like Metamask, where they have a list good, known tokens that are always shown to the user, but the user can still add a custom token by address.

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I think the best approach would actually be the combination of the two: pre-curated list of tokens, ability to add custom tokens, AND the ability to hide tokens (e.g. if a token was added accidentally)