Switch to render-pass

This switches us to wlr_render_pass and to wlr_output_commit_state.

phoc_renderer_render_view_to_buffer keeps using wlr_renderer directly as it needs wlr_renderer_readpixels. This will be fixed when switching to 0.18.x and wlr_texture_read_pixels.

Ideas for this taken from sway.

This has still unfixed bits and disabled bits for server side decorations and debug options so very draft but runs here already.

It's currently on top of !522 (merged) and very rough so don't bother with it yet.

Closes: #344 (closed), #346 (closed)