Plot style modification for kl k2V 2D plots in paper

Plot style modification for kl k2V 2D plots in paper:

Modified latex text size of CMS and lumi in dhi/plots/likelihoods.py

Modified left and bottom margin in dhi/plots/likelihoods.py

Modified x and y axis title size in dhi/plots/likelihoods.py

Modified model parameter text size in modules/plotlib/plotlib/root/routines.py