Data loading of eclipse summary vectors

[lindjoha]

Problem:
I often have to reload webviz when changing ensembles or plugins. It takes a lot of time and is a bit frustrating when working.

Proposed solution:
The first time an ensemble is loaded, the summary data is stored in a file on the scratch disk (parquet-file?). The next time Webviz is loading the same ensemble it can just read the file which should be much faster.

[anders-kiaer]

Based on what @sigurdp has done through factory, and since we also have the "portable build option" (which is basically "store to data and make it quick afterwards"), I think this is done? Feel free to reopen if not.

We could prioritize/consider equinor/webviz-config#236 - in order to improve user communication further on this feature.