- Add LiveAsset account, payment method, AccountPayload
- Extract super classes for normal CryptoCurrenyAccount and payload and
LiveAssetAccount and payload
- Add isAsset method
- Add button for creating a live asset account

As it is a bit tricky to use the AccountForm for both methods and add a
checkbox there so defined which payment method to use I added a button
to add an AccountForm with the LiveAssets passed. This is just
temporary to be able to test a bit more and see if there are any
critical issues. We should unify that form but that might require a bit
of refactoring of the CryptoCurrencyForm.