Finish up @wc8 suggested user preferences: tags and Advanced Options

Last two user preferences in my mini-project about them!

* User can now show and hide tag list in task edit mode via click, just like Advanced Options.
* New user preference to have tags start off hidden when user first creates/edits a task.
* New user preference to have Advanced Options start off hidden when user first creates/edits a task.

The options default to `false` since they add extra clicks in many cases. The hidden-tags option is useful for power users who have lots of tags, and use the *secret technique* of creating tasks with filters active to assign tags. The hidden Advanced Options preference is useful for users who frequently make use of Extra Notes, checklists, and so on, but seldom use difficulties or attributes.