add additional Typoscript configuration for dependency scss.

[SCPhilippHolzmann]

I add a typoscript variable to define dependencies of a Scss file. I made this to allow other extensions to override scss variables of the dependencies.

Here is a example how the typoscript configuration look like
page.includeCSS{ customer = EXT:t3s_customer/Resources/Private/sources/Scss/customer.scss customer.dependencies { 5 = EXT:my_extension/Resources/Private/sources/scss/bootstrap/functions 10 = EXT:my_extension/Resources/Private/sources/scss/customer-variables } }

[svewap]

I personally would not make the SCSS files of my template extension dependent on another extension. That would be too uncertain for me. I would always prefer an independence. I would always copy the SCSS files of other extensions into my extension, because I usually modify them then.