Update File Access to code to refere to PublishPress Permissions

[stevejburge]

Currently it refers to Press Permit, the old plugin name

[agapetry]

@richaferry Note that this .htaccess comment tag is searched to find and update existing entries. As a result, if the string is changed, you will need to do either of the following:

• Change the existing insertWithMarkers() logic to check for both "BEGIN PublishPress Permissions" and "BEGIN Press Permit"

or...

• Implement of plugin update script to modify existing "BEGIN Press Permit" entries in the uploads/.htaccess file to "BEGIN PublishPress Permissions". This would need to be done regardless of whether the File Access module is currently enabled, or tied to execution of File Access module init rather than plugin activation.

[stevejburge]

OK, let's delay this to avoid any issues