base_initializr template fix, so no other than standard config needs to be added

After my work with #831 - I found some minor bugs where the base_initializr template didnt work with minimal configuration eg. no meta added to app/config.yml - So this is fixed now

TL:DR;
The template will now work with the configuration

````
mopa_bootstrap:
    form: ~  # Adds twig form theme  support
    menu: ~  # enables twig helpers for menu
````

Meaning that

````
mopa_bootstrap:
    initializr: ~
````

is not needed, as all tags used in base_initalizr will now be checked before added