Feature proposal: faster line drawing that does not affect the main thread as much

[andrew-raphael-lukasik]

This fork implements small external https://github.com/andrew-raphael-lukasik/Segments package. It's goal is to introduce simple and cheap line rendering for dots. It delivers on that to some extent but has few drawbacks too: no Shader Graph (as it doesn't allow geometry shaders) and orthographic projects is not really implemented yet (works but not perfectly there).

Feel free to reject this PR if you're not convinced. It's just my proposal to lower cpu usage for laser line drawing which I noticed was affecting the framerate in some cases (a lot of Fighter ships attacking at once).

[andrew-raphael-lukasik]

Note :

This PR is branched out from #7 PR, so probably better to consider #7 first.

It's basically just a single f22b9f47f4eb47518d90434c4ae2818fd48ef08b commit.

[ElliotB256]

I'll certainly agree the line drawing I have in there is very prototypical! My long term hope was that Unity would come along with a DOTS compliant particle system before too long, but its now clear that while take a while.

I'll review this properly when I get a chance