feat: wire up extras and conditional dependencies in rattler-build

[wolfv]

This tests that conditional dependencies and extras (optional dependency groups) work in rattler-build.

The recipe that I tested with looks like this:

package:
  name: conditional
  version: 0.1.0

requirements:
  run:
    - rattler-build
    - bzip2 *; if rattler-build >=0.44
    - zstd *; if rattler-build <0.44

  extras:
    science:
      - numpy
      - matplotlib
    web:
      - flask
    cli:
      - click

tests:
  - script:
    - echo "Hello, world!"
    requirements:
      run:
        - rattler-build >=0.44
  - script:
    - echo "This is a test for Rattler < 0.44"
    requirements:
      run:
        - rattler-build <0.44
  - script:
    - echo "This is a test for Rattler < 0.44"
    requirements:
      run:
        - conditional [extras=[science, web]]