Send funds don't use all available funds by default.

[refund-agent2]

Description:

When sending funds, wallet selects to spend all funds with the "use all available inputs" by default. That puts all funds at risk when sending to an unknown person, specially when changing tabs after introducing an amount, when the amount is back to the total amount.

Steps to reproduce:

An user sending funds could use the option to "use all available funds" because it's the default and doesn't mind about what specific utxo's to use.
Select to send 0.1BTC, go to the portfolio or another tab for whatever reason and then go back to send funds to complete the payment without realizing that the wallet is spending all the funds.

There is a popup to make sure what do you want to spend, but I think that this would be the only wallet that suggests to spend all funds by default.

Possible changes:

1. Use "Use custom inputs" by default and keep "use all available inputs the same. Probably takes less work and will invite users to care about what utxo's are spent.
2. "Use all available inputs" receiver's amount field is 0 by default.