Make --list-profiles argument more inclusive

Change the `provider` argument to search for the user-named providers or salt-cloud named providers. Returns providers names as given in the argument. 

For example:
```
$ salt-cloud --list-profiles my_linode_config
linode-profile-1:
    ----------
    my_linode_config:
        ----------
linode-profile-2:
    ----------
    my_linode_config:
        ----------
```
or
```
$ salt-cloud --list-profiles linode
linode-profile-1:
    ----------
    linode:
        ----------
linode-profile-2:
    ----------
    linode:
        ----------
```