New functions and vignettes

[wevertonbio]

• Use fPROC::auc_metrics() to calculate pROC.
• Implement new partition methods: kfolds, subsample, bootstrap and leave-one-out.
• Update all data (prepared_datas, calibration_results and fitted_models) to match new partition methods.
• Document example datasets.
• New vignette explaining how to explore model uncertainty and variability.
• color_for_changes(): new function for setting colors for change maps. Function used and detailed in the vignettes.
• organize_for_projection(): new function to manually organize and structure variables for past and future projections
• New vignette explaining how to use the organize_for_projection function.
• Add CHELSA LGM variables to inst/extdata for vignette examples.
• Add option in MOP to fill in-range areas with zeros instead of NAs
• Fix error when subsetting scenarios in import_projections() and add option to import mop distance.
• Include example data and detailed guidance in prepare_data vignette on using data partitions with spatial blocks generated by external packages (ENMeval and flexsdm)
• Remove unused data objects: calib_results and sp_swd_cat.
• Minor changes in some examples to reduce testing time from over 5 seconds to under 5 seconds
• Fix links in vignettes
• Update website