Plugin settings for private status

[agileware-pengyi]

Regarding #24
After the PR merged, if the event is set to not public, the post will be private until someone changes it in the post.
As discuss, we can have

• a setting for overriding status
• sync status from EO to civi

Agileware ref: CIVIEO-3

[em-piguet]

Hello, I think an admin setting for this would be a nice addition to the plugin.
For us the trust source is the civi event not the Event Wp. So if we change the public setting in Civi we expected the wp event status to change.