Add context menu to the Tabbar

[neSpecc]

Currently, we can’t interact with multiple open tabs. Default browser context menu is open instead:

1. Handle Right clicks on the Tab
2. Add Popover with ContextMenu inside
3. Implement "Close", "Close Others", "Close to the right", buttons

You can see Context Menus in VSCode, or browser as a reference

In future, we'll add "Pin", "Copy path" button.