This patch uses a graph flow scheduler for creating all mesh batches. On a Ryzen 1700 the framerate of Spring/020_02A.anim.blend went from 10 fps to 11.5 fps. For each mesh where batches needs to be updated a sub-graph will be added to the task_graph. This sub-graph starts with an extract_render_data_node. This fills/converts the required data from Mesh. Small extractions and extractions that can't be multi-threaded are grouped in a single `extract_single_threaded_task_node`. Other extractions will create a node for each loop exceeding 4096 items. these nodes are linked to the `user_data_init_task_node`. the `user_data_init_task_node` prepares the userdata needed for the extraction based on the data extracted from the mesh. Note: If the `lines` and `lines_loose` are requested, the `lines_loose` sub-buffer is created as part of the lines extraction. When the lines_loose is only requested the sub-buffer is created from the existing `lines` buffer. It is assumed that the lines buffer is always requested before or together with the lines_loose what is always the case (see `DRW_batch_requested(cache->batch.loose_edges, GPU_PRIM_LINES)` in `draw_cache_impl_mesh.c`). Reviewed By: Clément Foucault Differential Revision: https://developer.blender.org/D7618