[Feature Request]: grr serve `--exclude` option

[superbrothers]

Feature Request

I would like to have the --exclude option to specify files that are excluded target files to grr serve command.

We are currently managing dashboard files with the following directory structure.

❯ tree .
.
├── Makefile
├── ipmi-exporter
│   ├── ipmi_exporter-cluster.json
│   └── kustomization.yaml
├── kustomization.yaml
└── nvidia-gpu
├── Makefile
├── dcgm-exporter-dashboard.json
└── kustomization.yaml

If grr serve --only-spec ./ is run on this directory, you will get errors for files that are not dashboard data.

It would be nice if grr serve has --exclude option and use it like this.

grr serve --only-spec --exclude Makefile,*.yaml ./