Add pepsi format

[oleflb]

Why? What?

Adds a pepsi format command, which runs cargo format, taplo fmt, and ruff format.
Right now the command does not expose any of the options of the three tools, not sure whether we want that.

The second commit also contains a format of the entire repo

Fixes #

ToDo / Known Issues

If this is a WIP describe which problems are to be fixed.

Ideas for Next Iterations (Not This PR)

• integrate into CI

How to Test

• pepsi fmt

[knoellle]

For me, ./pepsi format fails with this error:

[ruff] ✗
   0: error: Failed to parse tools/machine-learning/mujoco/typings/mujoco/_specs.pyi:321:11: Expected an identifier
      error: Failed to parse tools/mujoco-simulator/mujoco-simulator/stubs/mujoco/_specs.pyi:321:11: Expected an identifier