[RenderEngine] Organize RenderEngine directory.

This patch:
1. adds proper namespace renderengine to all RenderEngine code,
   and namespace gl to all GLES related code
2. creates gl/ directory for GLES backend code
3. Reorder include header files, remove unused header files.

BUG: 112585051
Test: Build, flash, run display validation
Change-Id: I81f0b8831213607cde08562958f7c38ddaf4c9e6
diff --git a/services/surfaceflinger/BufferLayerConsumer.cpp b/services/surfaceflinger/BufferLayerConsumer.cpp
index aa8f4e1..fa181ad 100644
--- a/services/surfaceflinger/BufferLayerConsumer.cpp
+++ b/services/surfaceflinger/BufferLayerConsumer.cpp
@@ -54,7 +54,8 @@
 static const mat4 mtxIdentity;
 
 BufferLayerConsumer::BufferLayerConsumer(const sp<IGraphicBufferConsumer>& bq,
-                                         RE::RenderEngine& engine, uint32_t tex, Layer* layer)
+                                         renderengine::RenderEngine& engine, uint32_t tex,
+                                         Layer* layer)
       : ConsumerBase(bq, false),
         mCurrentCrop(Rect::EMPTY_RECT),
         mCurrentTransform(0),
@@ -592,7 +593,8 @@
     ConsumerBase::dumpLocked(result, prefix);
 }
 
-BufferLayerConsumer::Image::Image(sp<GraphicBuffer> graphicBuffer, RE::RenderEngine& engine)
+BufferLayerConsumer::Image::Image(sp<GraphicBuffer> graphicBuffer,
+                                  renderengine::RenderEngine& engine)
       : mGraphicBuffer(graphicBuffer),
         mImage{engine.createImage()},
         mCreated(false),