Implement local block bootstrap

[astrogilda]

Is your feature request related to a problem? Please describe.
Block bootstrapping is not directly applicable when the data isn't stationary. However, in several situations, the data is almost stationary and is slowly varying.

Describe the solution you'd like
Implementing a new class, LBB, inspired by this paper

Additional papers: https://link.springer.com/article/10.1007/s00184-012-0413-9