v3dv: implement VK_EXT_line_rasterization

Allow to choose the line rasterization algorithm. It supports
rectangular and Bresenham-style line rasterization.

v2 (Iago):
 - Update documentation.

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <!15407>