Support modify kernel-parameters for different arch in build image.

I have a use case where I need different kernel parameters for the same variant across different architectures. For example, for the `aws-dev` variant, if the architecture is `aarch64`, I want to add `"pci=realloc"` and remove `"quiet"`.

**Before:**
```toml
[package.metadata.build-variant]
kernel-parameters = [
# Other parameters omitted for clarity
"quiet",
]
```

**After:**
```toml
[package.metadata.build-variant]
kernel-parameters = [
"pci=realloc",
]
```

Could Twoliter add a feature to support this? Something like:
```bash
twoliter modify-kernel-parameters --variant "aws-dev" --add "pci=realloc" --remove "quiet"
```

It could be even better if the modification is integrated into the "cargo make build" command. Such that there is no `-dirty` tag of images built.

Start by tracing the existing twoliter modify-kernel-parameters command and the cargo make build flow mentioned in the issue. Determine where variant and architecture-specific kernel parameters are configured, then verify that adding and removing parameters produces the requested architecture-specific image without a -dirty tag.

Written by the indexing model from the issue text.