Develop benchmarks

[brzep]

PR for issue #937

Develop more benchmark options:

• resolution

  • presets
  • iteration

• outputs

  • iteration
  • maximize

• run without encoder

• run without decoder

• renamed encoder/decoder_count to output/input_count to be more meaningful

[brzep]

I am wondering what kind of resolution presets use to be meaningful and unambiguous. Maybe rename it to sth like Res1080p, Res480p, etc?

pub enum ResolutionPreset {
    Uhd,
    Qhd,
    Fhd,
    Hd,
    Sd,
}

[jerzywilczek]

We don't need global here, as we don't have subcommands.

Also, you can use default_value instead of Option

[brzep]

I don't think default_value changes much here, it's not used anyway if disable_encoder is present. Talking about defaults, I would highly consider adding default values to all parameters, so you don't need to specify all of them every time what is a bit inconvenient