Documentation: How to deploy Policies

### Documentation Issue

Hello,
It is possible to include some example how to deploy policies?

Example:
https://github.com/Azure/data-management-zone/blob/main/infra/Policies/PolicyDefinitions/Synapse/params.policyDefinition.Append-Synapse-Purview.json

This policy needs the value for "[parameters('purviewResourceId')]"

If we want to deploy to Subscription we can use:
`az deployment sub create -l northeurope -f deploy.policyDefinition.sub.json -p ./PolicyDefinitions/Synapse/params.policyDefinition.Append-Synapse-Purview.json`

But I fail to understand two things:

1) How we can pass the value for the parameter purviewResourceId
2) how to "mass" deploy multiple policies using a single parameter file

Thanks!

### Code of Conduct

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