Improve footprint by allowing element selection during static link stage
This MR intends to alleviate gstreamer-full library containing only a set of elements from a plugins. During the link stage of gstreamer-full, the dead code path will be removed and the final binary size will be smaller.
In this MR, two plugins have been split up following the scheme described in gstreamer!661 (merged)
This two plugins owns various element init method who needed to be relocated to different file in order to proceed to an efficient split of element.
Next plugins split will follow but this is a POC to discuss first.
For more details, please follow gst-build!199 (merged)