Split vulkan_base into smaller units

Closes #30. This is a basic refactoring of the graphics module, so
everything won't be in single file.

graphics/CMakeLists.txt

@@ -0,0 +1,61 @@
+find_package(Vulkan REQUIRED)
+find_package(glfw3 REQUIRED)
+find_package(glm REQUIRED)
+
+find_package(Vulkan COMPONENTS glslc)
+find_program(glslc_executable NAMES glslc HINTS Vulkan::glslc)
+
+cmake_policy(SET CMP0116 NEW)
+function(compile_shader)
+    cmake_parse_arguments(PARSE_ARGV 1 arg "" "ENV;FORMAT" "SOURCES")
+    foreach(source ${arg_SOURCES})
+        message(${source}.${arg_FORMAT})
+        add_custom_command(
+                OUTPUT ${source}.${arg_FORMAT}
+                DEPENDS ${source}
+                DEPFILE ${source}.d
+                COMMAND
+                ${glslc_executable}
+                -o ${source}.${arg_FORMAT}
+                    ${CMAKE_CURRENT_SOURCE_DIR}/${source}
+                    )
+    endforeach()
+endfunction()
+
+
+
+compile_shader(rse_graphics
+ENV opengl
+FORMAT num
+SOURCES
+shaders/shader.vert
+shaders/shader.frag
+)
+
+add_library(rse_graphics SHARED shaders/shader.vert.num shaders/shader.frag.num)
+target_include_directories(rse_graphics PRIVATE
+${PROJECT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_SOURCE_DIR}
+    ${Vulkan_INCLUDE_DIR}
+    ${glfw3_INCLUDE_DIR}
+    ${glm_INCLUDE_DIR}
+)
+
+
+target_sources(rse_graphics PRIVATE
+    src/window.cpp
+    src/vulkan_base.cpp
+    src/vulkan_pipeline.cpp
+    src/vulkan_buffers.cpp
+    src/vulkan_descriptors.cpp
+    src/rse_graphics.cpp
+)
+
+target_link_libraries(rse_graphics PRIVATE
+    rse_utilities
+    ${Vulkan_LIBRARIES}
+    glfw
+    glm
+)