This change add a CMakeLists in each of the following folders, and
creates the following targets:

src/Common -> gl_common
src/Main -> gl_main
src/Renderer -> gl_renderer
src/Shader -> gl_shader

Bug: b/145758253
Change-Id: Ia1f68d0689f80955586235e125e0197da25d692d
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43550
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>