[Console] added ability for the Default Command to receive options

The previous implementation, while using ArrayInput, was lacking the abilty to
pass the options to the Default Command. Updated the code to use StringInput
instead, and pass the options (string) from the original command to the default one.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

- [x] submit changes to the documentation ( https://github.com/symfony/symfony-docs/pull/3973 )

why not `'' === $val`?