Use structured source data for version IDs (#18840)
## Summary
Right now, two direct URLs with different hash fragments are considered
different versions based on `VersionId`. This PR changes the internal
representation to match our parsed URL structure. E.g., these should be
considered the same "version" if specified as direct URLs:
```text
https://files.pythonhosted.org/packages/36/55/ad4de788d84a630656ece71059665e01ca793c04294c463fd84132f40fe6/anyio-4.0.0-py3-none-any.whl#sha256=cfdb2b588b9fc25ede96d8db56ed50848b0b649dca3dd1df0b11f683bb9e0b5f
https://files.pythonhosted.org/packages/36/55/ad4de788d84a630656ece71059665e01ca793c04294c463fd84132f40fe6/anyio-4.0.0-py3-none-any.whl#sha512=f30761c1e8725b49c498273b90dba4b05c0fd157811994c806183062cb6647e773364ce45f0e1ff0b10e32fe6d0232ea5ad39476ccf37109d6b49603a09c11c2
```
