split `examples/` into `benchmarks/` and `bins/` (dragoon/komodo!117)

## new structure for the repository
- benchmarks are in `./benchmarks/` and can be run with either `cargo run --package benchmarks --bin <bench>` or the commands in `./benchmarks/README.md`
```
├── Cargo.toml
├── README.md
└── src
    └── bin
        ├── commit.rs
        ├── fec.rs
        ├── linalg.rs
        ├── operations
        │   ├── curve_group.rs
        │   └── field.rs
        ├── recoding.rs
        ├── setup.rs
        └── setup_size.rs
```

- examples are now in `./bins/` as standalone binaries and can be run either with `cargo run --package <pkg>` or with the help of the `cargo bin` command from `.nushell/cargo.nu`
```
├── curves
│   ├── Cargo.toml
│   ├── README.md
│   └── src
│       └── main.rs
├── inbreeding
│   ├── build.nu
│   ├── Cargo.toml
│   ├── consts.nu
│   ├── mod.nu
│   ├── plot.nu
│   ├── README.md
│   ├── run.nu
│   └── src
│       ├── environment.rs
│       ├── main.rs
│       └── strategy.rs
├── rank
│   ├── Cargo.toml
│   └── src
│       └── main.rs
└── rng
    ├── Cargo.toml
    └── src
        └── main.rs
```

- Nushell modules are now located in `./.nushell/`

## changelog
apart from the changes to the general structure of the repo:
- `binary.nu` -> `.nushell/binary.nu`
- new `cargo bin` command from `.nushell/cargo.nu`
- `error throw` is now defined in `.nushell/error.nu`
- main TOML has been greatly simplified because the dependencies of "examples" have been moved to the associated crates
- the rest is basically the same but in the new structure