text: Title: [Feat] Export grammar of plots
  Body: It would be really great to be able to export and import a description of the graph for later reuse, like it is done in Vega.
  This also relates to [[Feat] Force data types in code #70 ](https://github.com/Kanaries/pygwalker/issues/70).
  Besides not having to setup predefined data types every time this would enable users of PyGWalker to export predefined setup of the plots in its entirety.