Implement SVG image file cache system

Implement SVG image file cache system

Let we cached svg image file load result, and rasterized texture as specific size.

For image url, let we cache Dali::VectorImageRenderer, which connect with vector rasterize engine.

For each rasterize request, we will use that cached id of loader, and Rasterize width/height.
If we use same size for rasterizing, we can share same Texture.

Change-Id: I9684557d2edabee0a749a39f428014c5a0cd27ff
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>