[Feature]: Creat a dedicated integrator class and use it across different samplers/SDEs/ODEs

[soran-ghaderi]

What is the problem you're trying to solve?

Currently, the integrators are hardcoded and not generalizable.
eg, hmc_step -> this should be inherited from a Leapfrog-verlet integrator and langevin should be euler-maruyama solver

Proposed Solution

• Implicit (Backward) Euler
• RK45 with adaptive step sizes

Example Usage (optional)

Alternatives Considered (optional)

No response

Additional Context (optional)

No response