[Routing] Export route definitions in yml, xml or php format

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8334
| License       | MIT
| Doc PR        | -

[Routing] Added classes to export route definitions. Added three export drivers: yml, xml and php.
[FrameworkBundle] Added command to export route definitions.

Annotations are great way to define your routes, but the usage of annotations when using for example Ioncube Php encoder is not supported. The command can export the route definitions in yml, xml or php formats to be able to use the encoder.