Enhancement to Show External Authentication Configuration

- Added new entry in the appliance console summary screen
to show a new "External Auth:" entry indiciating either
"not configured" or the IPA Server hostname.
- Also showing current external authentication configuration
before giving the option to unconfigure.

Note: diff best viewed/understood while ignoring whitespace via https://github.com/ManageIQ/manageiq/pull/202/files?w=1

This is fine, but you might want to try the new awesome_spawn params format which is a lot friendlier...For example this could be:

```ruby
AwesomeSpawn.run!(IPA_INSTALL_COMMAND,
                  :params => {"-N"           => nil,
                              :force_join    => nil,
                              :realm=        => realm,
                              :domain=       => domain,
                              :server=       => server,
                              :principal=    => principal,
                              :password=     => password,
                              :fixed_primary => nil,
                              :unattended    => nil})
```

Or, with the simpler barewords style:

```ruby
AwesomeSpawn.run!(IPA_INSTALL_COMMAND,
                  :params => [
                    "-N", :force_join, :fixed_primary, :unattended, {
                      :realm=     => realm,
                      :domain=    => domain,
                      :server=    => server,
                      :principal= => principal,
                      :password=  => password,
                    }
                  ]
```