Add flag to text command to allow passing custom list of tools

User should be able to pass a custom list of tools via cli command. This list can get appended to the existing list of supported tools [here](https://github.com/chaoss/disclosure/blob/main/detection/constants.go#L29-L52) and be used with toolmentions. So any list (huggingface, openrouter, etc. or both combined) can be used.

The command would be something like:
```sh
disclosure text --custom-tools=tools_list.json --input=textfile.txt
```

And tools_list.json structure can be:
```json
{
"custom_tools": ["tool1", "tool2", ...]
}
```

Related: #42.