Hide more ways the hidden content might still appear

• Changed shadow-hidden content to use the private model API of Flarum, this prevents the content being used/shown in discussion meta, tag meta and some notifications and other usage by third-party extensions
• Explicitly silenced all notifications from flarum/mentions and flarum/subscriptions, including to moderators/admin
• No longer automatically shadow hide the first post of a discussion since the discussion is already shadow hidden itself
• Added "deleted" styling to shadow-hidden discussions in discussion list
• Added events for third-party extensions to hook into

You need to run migrations after updating, until this is done all previously shadow-hidden content will be visible to everyone. Use php flarum migrate or disable and re-enable the extension to do so.

Bugfixes

• Prevent entering invalid values for TIMESTAMP column (can't ban past year 2038) #2
• Remove leftover console.log #3

Bugfixes

Fixes blank error page for non-admins when "Hide shadow banned users profiles" option is enabled

First release

For Flarum 1.0+