Change ACL json input structure to be less ambiguous for restrictions

The restriction details in the security:acl contentloader json input can be ambiguous in some situations.

This is the ContentLoader equivalent for what was done for SLING-11243 and SLING-11233

Expected:

The JSON structure of the security:acl entries should be enhanced to make it more clear. 

For example, replace the "granted/denied/restrictions" items with a "privileges" structure whose items are the granted or denied privileges.  Each privilege has a "deny" and/or "allow" child whose value is either true (no restrictions) or an array of restrictions + values.

For example:

    "security:acl": [
        { 
            "principal": "sling123_user", 
            "privileges":{
                "jcr:read": {
                    "allow": true
                },
                "jcr:write":{
                    "allow":{
                        "rep:glob":"glob1allow"
                    },
                    "deny":{
                        "rep:glob":"glob1deny"
                    }
                }
            }
        }
    ] 

The previous syntax should be preserved for backward compatibility.