This patch adds the possibility to attach video metas to allocated buffers if
API users request that option.
The main reason to add this meta is for the future usage of
gst_buffer_find_memory(), where the requested offset determines the memory
index.
In the case of multi-memory Vulkan images the offset of every component is
larger than the default offset determined by the format and frame size, because
of the buffer minimum size and memory alignment determined by the used driver.
Then, the offset is set in the buffer video meta.
In the case of single memory Vulkan images, the default offset is set in the
video meta.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9219>
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