Vector network support

[harry75369]

Detailed description

Currently vgg_runtime does not support vector network data input, which is defined by VGG Specs here (https://docs.verygoodgraphics.com/specs/vectorgraphics/vector-network)

Possible implementation

The support of vector network could be divided into two phases:

1. Compatible support phase. In this phase, runtime shall convert vector networks data into the traditional path data (defined in VGG Specs) so that vector networks could be correctly displayed without introducing fundamental data structure refactoring in runtime.

2. Full support phase. In this phase, runtime shall make a fundamental refactoring about vector data representation. Full unit tests should also be included if runtime switches to vector networks over traditional path representation as its core data structure.

Additional information

No response