FR: Allow storing comments in ACL grants as a JSON field

### What are you trying to do?

Allow access controls JSON to have comments for notes / other team members directly in rules.

```
"grants": [
{
"//": "bitbucket pipelines sync job for platform access",
"src": ["tag:bitbucket-jenkins-sync"],
"dst": ["svc:jenkins-core"],
"ip": ["443"]
},
]
```

### How should we solve this?

_No response_

### What is the impact of not solving this?

_No response_

### Anything else?

_No response_