Optional dependencies support in libsolv

[prsabahrami]

Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

To support optional dependencies in libsolv.
Specifically, the details should be similar to the implementation of the feature in rattler for resolvo.

• The repodata records contain an extra field called extras which are of the below form and indicate the optional dependencies of a package.

"cuda-version-12.5-hd4f0392_3.conda": {
  "depends": [],
  "constrains": [
    "__cuda >=12.1"
  ],
  "license": "LicenseRef-NVIDIA-End-User-License-Agreement",
  "version": "12.5",
  "extras": {
    "with-cudadev": [
      "foo >=4.0.2",
      "bar >=1.2.3"
    ]
  }
}

Why is this needed?

No response

What should happen?

No response

Additional Context

No response