Add OffScreenCanvas/web worker integration

[sev-b]

I am currently working with big datasets (>1 million datapoints) and even with manual updates, no animation, etc. setOptions stalls my application for a noticeable amount of time so handling echarts in a separate web worker would be a great addition for me

There are already requests for integration of web workers (& OffscreenCanvas) for echarts and another developer created this handy package. But as of now it seems like quite a pain to make this work with vue-echarts