--extra cli option is nonfunctional

Puppet Version: 5.5.1
Puppet Server Version: N/A
OS Name/Version: Centos 7.4.1708

Many `puppet` applications such as `puppet facts` and `puppet catalog` take a `–terminus` option to specify what indirector to use. These applications generally also specify a `–extra` argument, like so:

`--extra HASH                  - Extra arguments to pass to the indirection request`

As far as I can determine, this argument is not actually possible to use, since any argument supplied to the `–extra` option is treated by Ruby as a String. For example, `puppet facts --terminus network_device --extra '{target => "example-device"}'` results in `Error: Could not call 'find' on 'facts': undefined method `inject' for "{target => \"example-device\"}":String`

The same results are had when trying other hash-ish syntaxes such as JSON or key-value pairs.

If there's some existing syntax that will actually work here, it should be documented. But I had a look through the source code, and I don't think any such syntax exists.

Describe steps to reproduce…

`puppet facts --terminus network_device --extra <anything at all here>`

Desired Behavior:

**The `–extra` argument should function, or should be removed.

Actual Behavior:

```

$ sudo puppet facts --terminus network_device --extra '{target => "example-device"}' --trace
Error: Could not call 'find' on 'facts': undefined method `inject' for "{target => \"example-device\"}":String
Did you mean? inspect
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/request.rb:68:in `initialize'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:115:in `new'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:115:in `request'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:187:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/face.rb:46:in `call_indirection_method'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/face.rb:84:in `block (2 levels) in <class:Face>'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/interface/action.rb+eval[wrapper]:264:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/face_base.rb:247:in `main'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:383:in `run_command'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:375:in `block in run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:661:in `exit_on_fail'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:375:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:137:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:73:in `execute'
/opt/puppetlabs/puppet/bin/puppet:5:in `<main>'
Error: Could not call 'find' on 'facts': undefined method `inject' for "{target => \"example-device\"}":String
Did you mean? inspect
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/request.rb:68:in `initialize'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:115:in `new'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:115:in `request'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:187:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/face.rb:46:in `call_indirection_method'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/face.rb:84:in `block (2 levels) in <class:Face>'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/interface/action.rb+eval[wrapper]:264:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/face_base.rb:247:in `main'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:383:in `run_command'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:375:in `block in run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:661:in `exit_on_fail'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:375:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:137:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:73:in `execute'
/opt/puppetlabs/puppet/bin/puppet:5:in `<main>'
Error: Try 'puppet help facts find' for usage

```