grapher - loadSubFolders

## Current State Of Affairs
- grapher only supports loading a folder with **basis.csv**, **time.csv** and **probs.csv** in it
- `loadFolder` redraws entire graph
## Objectives
- [ ] Separate `loadFolder` and `clearAllLineSeries` in UI
- [ ] Add option to load a directory recursively (one layer) and display data from all sub-directories on a GraphView