Unhardcode font resolution

Currently when fonts are loaded they receive a hardcoded path:
https://github.com/stride3d/stride/blob/master/sources/engine/Stride.Graphics/Font/FontHelper.cs#L6
and will only be resolved using the odb filesystem:
https://github.com/stride3d/stride/blob/master/sources/engine/Stride.Graphics/Font/FontManager.cs#L266

So im requesting a change to un-hardcode this. In a perfect-scenario this uses the VFS, and the path resolution can be set by the project.

This makes it hard for full-code-only projects which load assets from a custom structure on runtime to load fonts. A workaround for this currently is:

        private SpriteFont FontNewDynamic(
            float defaultSize,
            string fontName,
            FontStyle style,
            FontAntiAliasMode antiAliasMode = FontAntiAliasMode.Default,
            bool useKerning = false,
            float extraSpacing = 0f,
            float extraLineSpacing = 0f,
            char defaultCharacter = ' '
        )
        {
            const BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Instance;
            var fontManager = ((FontSystem)this.Font).GetType().GetProperty("FontManager", flags)?.GetValue(this.Font);

            if (fontManager?.GetType().GetField("cachedFontFaces", flags)?.GetValue(fontManager) is not Dictionary<string, Face> cachedFontFaces
                || fontManager.GetType().GetField("freetypeLibrary", flags)?.GetValue(fontManager) is not Library freetypeLibrary)
                return this.Font.NewDynamic(defaultSize, fontName, style, antiAliasMode, useKerning, extraSpacing, extraLineSpacing, defaultCharacter);

            using var fontStream = File.OpenRead($"Assets/Fonts/{fontName}.ttf");
            var newFontData = new byte[fontStream.Length];
            fontStream.Read(newFontData, 0, newFontData.Length);

            lock (freetypeLibrary)
                cachedFontFaces[FontHelper.GetFontPath(fontName, style)] = freetypeLibrary.NewMemoryFace(newFontData, 0);

            return this.Font.NewDynamic(defaultSize, fontName, style, antiAliasMode, useKerning, extraSpacing, extraLineSpacing, defaultCharacter);
        }

Start with sources/engine/Stride.Graphics/Font/FontHelper.cs at the hardcoded path and FontManager.cs around line 266 to trace how font files are resolved. Compare that flow with the VFS and the provided runtime workaround; done means a project-configurable resolution path lets full-code-only projects load fonts from custom runtime structures without reflection-based access.