echarts bar chart performance improvements

[thinkh]

Coming from #497 (review) we still have some performance issue when rendering a large number of categories, groups, and/or facets. It also depends on the number of items per category, group, facet that needs to be processed (e.g., calculate the avg, ...). The performance get's noticably worse when sorting the bar chart. Please check if the performance can be improved for these kind of datasets.

Some suggestions (but not complete) for performance improvements:

• virtualization per facet -> improves the performance for large number of facets (@oltionchampari started with this)
• avoid re-render the whole chart when sorting is applied to the config and default; the chart is rendered in the initial order and then re-rendered when the sorting finishes
• update the bar chart on the fly with dynamic data update, which might be faster than re-rendering the whole chart from scratch

[thinkh]

See also my related comment about animations and merging the series data.

[oltionchampari]

@dvmoritzschoefl One use case that we need to support (currently) is having a bar with 10k+ bars. Currently, this freezes the application and then crashes.

[dvmoritzschoefl]

@oltionchampari @thinkh for coordination:
I made a PR on ollys branch that fixes some virtualization issues. Previously when the config changed all plots were remounted caused some flickering
https://github.com/datavisyn/visyn_core/pull/518/files