When a user is using `metadata` attribute, we do not write anything to `WORKSPACE`.

Eventually, the writing of data to `WORKSPACE` will be removed in a breaking change release.

Previously, the canonical arguments were blatted over any previously existing `WORKSPACE`.

This was stupid. It now appends to the file if it exists.

Eventually, in a breaking change we will remove this functionality as it is superseded by `metadata` attribute.

Jonathan Watson authored Feb 26, 2025 and Matthew Clarkson committed Feb 28, 2025

```py
download_file(
    name = "example",
    metadata = {
        "//:integrity.tmpl.bzl", ".integrity.bzl",
    },
)
```

Where `integrity.tmpl.bzl` is:

```py
visibility("public")

INTEGRITY = "{{integrity}}"
```

Then `@example//:.integrity.bzl"` can be used in `load` statement to read the download integrity.

Removes a circular dependency. `rules_diff` indirectly depends on `download_utils`.

Removes `reuse` support.

Will be disabled by default in Bazel 9.

We exclusively use `MODULE.bazel`.

Remove legacy workspace.

Bazel resolves transitive versions based on the `compatibility_level` and
can chose a newer version that what is specified in `MODULE.bazel`.

The warnings are often noise as we are happy to use newer versions, we
just specify the minimum version we are compatible with in `MODULE.bazel`.

Includes breaking change to `toolchain_local_select` which
does not affect this module but is a needed updated for Bazel 8