InfoBar to warn users about hidden items not showing in the sidebar

[IviriusMain]

Put an InfoBar in the settings to warn users that any hidden folders won't show in the sidebar in Wino Mail

[bkaankose]

I would take it further:

• All folders must be synced to local
• If they are hidden from the API, they will be synced hidden.
• Folder Options must have a toggle to hide optionally.