Remove parameters related to distribution search and change default

[amontanez24]

Problem Description

Since the univariate distribution search seems to be slow, we want to remove this option from the user facing API and replace it as the default.

Expected behavior

• The GaussianCopula and CopulaGAN tabular models should default to truncated_gaussian since that can fit most distributions
• univariate, parametric, bounded, semi_bounded, parametric_bounded, parametric_semi_bounded should be removed from the _DISTRIBUTIONS dict and from the docstring in the readme.
• Users should still be able to provide all other distributions (beta, gaussian, gamma, student_t, gaussian_kde, truncated_gaussian)

[fealho]

@amontanez24 Should I delete it from the tutorials as well?

[amontanez24]

@amontanez24 Should I delete it from the tutorials as well?

@npatki I'd say yes right?