[Composer] Fixing composer.json to work with newer symfony and without mongodb

Fixed version string for ```symfony/framework-bundle```

I removed the unnnessecary Zend modules and moved them into require-dev,
since I couldn't find any references to the DoctrineModule or
DoctrineORMModule inside the source code.

I moved the requirements for ```doctrine/mongodb``` and
```doctrine/mongodb-odm``` into require-dev and suggest, so a notice is
displayed if someone wants to use it with ODM.