What does this PR do?

• Implement plugin talk-plugin-author-menu that displays a popup menu when clicking on a user.
  • New Slots: authorMenuInfos and authorMenuActions.
• Implement plugin talk-plugin-member-since to display the registration date in the author menu
• Refactor ignore user feature into plugin talk-plugin-ignore-user.
  • Remove caret and show a ignore user button in author menu instead
  • Move stop ignoring user feature into plugin and insert into new slot profileSections.
• Refactored isCommentIgnored
• Fixed some fragment tree assembling bugs.
• Fix notification bug (pym based).

How do I test this PR?

• Ignore a user
• Unignore a user