Bicep Deploy for Params

#### Setting Deployment Properties in Param Files (Bicep Deploy)
- I can set the deployment properties for the Bicep template in the parameter file
- I can override the set deployment properties in the command line on deployment
- I can choose whether to include values for optional deployment properties
- I can import other bicepparam files
- Example:
```
deploy './main.bicep' {
location: 'West US'
mode: 'Incremental'
name: 'deploy-prod'
group: 'myRg'
}
```

The issue names Bicep deploy parameter files and bicepparam imports, but no files, tests, or entry points. Start by locating the Bicep deploy and parameter-file implementation, then trace how deployment properties are parsed and overridden. Done means the listed properties, command-line overrides, optional values, and imports work as described.

Written by the indexing model from the issue text.