Basis for refactoring nanovg GL3 render
Refactoring nanovg rendering code - use more DSA GL API
Commiting modified solution in order to add Med project
NVG: use gpu frame buffer for allocations; added profiling markers
Uses gfx standard vao for rendering
nanovg: use gpu frame dynamic buffer for vertices
Improved performance of nanovg - disabled AA and stencil rendering of strokes
Fixed double free crash
NanoVG backend refactoring:
 - shader is created outside of context initialization code
 - removed all glGetError checks
 - replaced few binding API with  DSA  API