This is a follow-up of MDL-73008, a few minor things have been found

1. WebService tool_policy_set_acceptances_status doesn't allow changing previous versions status
In LMS, users can change the status of all policies if they have the right capability, even if the version changed isn't the latest version of a policy. However, the WebService tool_policy_set_acceptances_status only allows changing the status of the latest version of each policy. This is because it uses the following call to validate the policies:

api::list_current_versions(policy_version::AUDIENCE_LOGGEDIN)

For consistency, the WebService should also allow changing the status of old versions too.

2. WebService tool_policy_get_user_acceptanaces should also indicate if a user can accept policies in general
This is required in order to display or not the Accept/Decline/Withdraw options

3. Allow to add notes while accepting or declining as the API already supports it