ssh should always specify the user name

[jandubois]

Hypothetical situation: I use a company laptop, and device management software forces me to use some LDAP identity as the local user name, say JDubois. But for all my VMs and lab machines I use jan as the user name. Therefore I create an ~/.ssh/config with explicit entries for a couple of official servers using my LDAP identify, and a fallback for my lab:

Host *
     User jan
     ForwardAgent yes
     UseKeychain yes
     AddKeysToAgent yes
     IdentityFile ~/.ssh/jan
     IdentitiesOnly yes

This currently breaks lima because it would create a JDubois user in the guest VM, but tries to connect with a jan user because of the config definition.

Always specifying the user in ssh commands avoids this potential error situation.