Improve `configs` defaults handling

[OverLordGoldDragon]

FEATURE: in visuals_gen and visuals_rnn, configs will now keep values of dicts of defaults, unless specifying the same keys. E.g.:

defaults = {'1': dict(a=1, b=2), '2': dict(c=3, d=4)}
configs  = {'1': dict(a=3, g=5)}
kw = {'1': {'a': 3, 'g': 5, 'b': 2}, '2': {'c': 3, 'd': 4}}  # AFTER
kw = {'1': {'a': 3, 'g': 5},         '2': {'c': 3, 'd': 4}}  # BEFORE

Also will apply deepcopy(configs) to not affect external dict.