Container parameters in Route#condition

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | no
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Adds ability to use parameters in route conditions like you can use them in container definitions:

```php
contact:
    path:     /contact
    defaults: { _controller: AcmeDemoBundle:Main:contact }
    condition: "request.headers.get('User-Agent') matches '%allowed_user_agents%'"
```

As you could see replacement of the placeholder happens before ExpressionLanguage will tokenize and compile the expression so it looks kinda ad-hoc and primitive.

This PR is a different implementation of #12869 which is I think is too overcomplicated for this feature.
This is why I added the note about how primitive this implementation is. It will replace said parameter (or raise an exception in case it is not defined). On the other hand you can escape percentages by typing them twice