As a moderator I want to prepare a meeting, but skip some (automatically added) topics to focus my meeting on other topics.

• On non-finalized meetings it is possible to mark/un-mark a topic as "skip".
• Menu: "glyphicon-eye-close Set Skip" / "glyphicon-eye-open Unset Skip"
  after "Set Recurring".
• A skipped topic is not included in "agenda mails" / "finalize" InfoItem & ActionItem mails
• A skipped topic shows the "glyphicon-eye-close" next to the "..." menu button
• A skipped topic's subject is displayed with strike-through font style
• Nevertheless it is possible to edit a skipped topic (add II, add AI, delete topic, ...)
• A skipped topic will automatically be opened and its checkbox is disabled
• A skipped topic should only be visible for moderators
• A skipped topic will show up in the next meeting as non-skipped
• A skipped topic will show "as normal" in the meeting series "all time topics" list
• The filter "Hide closed topics" should also hide skipped topics
• Add E2E test (check sent EMails)
• Update UserDoc