Pick bank account by label name instead of address

[wiwichips]

Portal bank accounts are guaranteed to have a unique name,

well, there are some accounts which have multiple accounts with the same name, and technically you can create multiple accounts with the same name as theres no restriction on the backend, but we block the ability to create multiple bank accounts with the same name on the frontend and expect accounts to have a unique name

so we should allow the user to choose a bank account by its name "label" instead of account address. This is simpler and more congruent with the wallet api

[wiwichips]

will be closed by #9