Use std::span or iterator pairs for arguments instead of std::vector

[johannesugb]

Currently within Auto-Vk and Gears-Vk, when a function/method supports multiple elements for one particular argument, that argument's type is std::vector. That is bad, however, since users are forced to use std::vector. Better: Use std::span! Even better: use iterator pairs, just like the STL does, but the problem is that then everything must be templated, I guess. So, no need to change everything to templated code, but if possible at some place => do it!

Definition of done:

• std::span<T> is used for arguments instead of std::vector<T> wherever the elements must be provided in contiguous memory (or if the affected code would have to be restructured too severely).
• Pairs of iterators are used for arguments instead of std::vector<T> wherever it can be implemented in a straight-forward manner.
• std::vector<T> is no longer used for passing arguments supporting 0..n elements
• The coe is well documented and the Contribution Guidelines have been followed.