Make SCP and SSH Tasks password field optional

Currently, there are 2 ways to configure SSH/SCP tasks:

• using password authentication
• using SSH keys, where I must specify the key file.

However, our usecase is different. We manage the SSH keys with puppet and as such we don't need to configure the SSH key in each of the plans.
We would like to use SSH task, but we can't because it requires to select the file key, whereas this is already handled by .ssh/authorized_keys and the default ~/.ssh/id_rsa key that is on the account on which the Bamboo itself is running.

If possible, I would add another option "Custom authentication" with only username and hostname options.