[WIP] bootstrap project specifics custom demo bundle and component

                   
|Q            |A  |
|---          |---|
|Bug Fix?     |n  |
|New Feature? |n  |
|BC Breaks?   |n  |
|Deprecations?|n  |
|Tests Pass?  |n  |
|Fixed Tickets|   |
|License      |MIT|
|Doc PR       |   |
                   

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i wonder if this can fly out, because stores are always customized it would be nice to see how can the sylius store be customized in a decoupled way, at least with a simple example of extension.