Open bookmark in Container Tab par Rob W

Adds an "Open in Container Tab" menu item to bookmark menus to open bookmarks in a container tab.

Container tabs are only supported in non-private browsing windows, so the add-on cannot open container tabs in private browsing windows.

The menu item will appear at the bottom of the context menu by default.
If you are an advanced user and want to move the menu item near the top (with the other "Open in ..." menu items), follow my instructions at https://github.com/Rob--W/bookmark-container-tab/issues/4 .