This function plots a world map and color the affected geographical region(s)
from light (lower) to dark (higher), depends on the cumulative number of sequences.
Aside from the plot, this function also returns a dataframe with 2 columns: 'Region' and 'Number of Sequences'.
The input dataframe of this function is obtainable from metadata_extraction(), with NCBI
Protein / GISAID (EpiFlu/EpiCoV/EpiPox/EpiArbo) FASTA file as input.