add cheap blur filter and composite bloom compute passes.

projects/bloom/CMakeLists.txt

projects/bloom/resources/Sponza/Sponza.bin

projects/bloom/resources/Sponza/Sponza.gltf

projects/bloom/resources/Sponza/background.png

projects/bloom/resources/Sponza/chain_texture.png

projects/bloom/resources/Sponza/lion.png

projects/bloom/resources/Sponza/spnza_bricks_a_diff.png

projects/bloom/resources/Sponza/sponza_arch_diff.png

projects/bloom/resources/Sponza/sponza_ceiling_a_diff.png

projects/bloom/resources/Sponza/sponza_column_a_diff.png

projects/bloom/resources/Sponza/sponza_column_b_diff.png

projects/bloom/resources/Sponza/sponza_column_c_diff.png

projects/bloom/resources/Sponza/sponza_curtain_blue_diff.png

projects/bloom/resources/Sponza/sponza_curtain_diff.png

...ects/bloom/resources/Sponza/sponza_curtain_green_diff.png

projects/bloom/resources/Sponza/sponza_details_diff.png

projects/bloom/resources/Sponza/sponza_fabric_blue_diff.png

projects/bloom/resources/Sponza/sponza_fabric_diff.png

projects/bloom/resources/Sponza/sponza_fabric_green_diff.png

projects/bloom/resources/Sponza/sponza_flagpole_diff.png