Make project storefront-build and project admin-build smart, too

[amenk]

project ci is "smart" enough to understand that plugins bring their pre-build stuff and don't build them. SwagCommercial assets should be never built in your pipeline as they are provided in their zip

Originally posted by Soner (@shyim) in #286

Would it make sense to add a switch to the above commands to not build stuff which is already built (i.e. built only custom/static-plugins) ?

.. also for the watch commands (which already have a skip / only list), but maybe a --skip-prebuild option would do?

[amenk]

Soner (@shyim) does this make sense for you? or am I doing the local dev update wrong? Do you also use shopware-cli project ci locally or are there other options I did not see?