Add file conversion and logo options to multi_panel setting in plot_forecast_map.R, plot_extreme_probs.R and plot_metrics.R

Bugfix: Ensure daily max/min variables (e.g. tasmin, tasmax) are loaded...

See merge request !199

Visualization unit test for decadal metadata

See merge request !196

Improvements to orography correction

See merge request !198

Modification to avoid faliure when fileout has duplicated slashes in test-decadal_visualization_metadata.R

Add Unit test to detect hard-coded absolute paths in R scripts

See merge request !132

Dev test visualization module metadata

See merge request !185

Dev plot extreme probabilities

See merge request !184

Update return_elements list in plot_forecast_map.R, plot_metrics.R and plot_most_likely_terciles_map.R