Control which native messaging hosts users can use

Setting the policy specifies which native messaging hosts aren't subject to the deny list. A deny list value of * means all native messaging hosts are denied unless they're explicitly allowed. All native messaging hosts are allowed by default. However, if a native messaging host is denied by policy, the admin can use the allow list to change that policy. Example value: com.native.messaging.host.name1 com.native.messaging.host.name2