App redesign UI follow-ups

[luke-quadratic]

• Re-add import button for creating file from CSV, XLSX, GRID, etc.
• Formatting bar states
• Keyboard shortcuts for sidebar items
• ~~Download as CSV hierarchy adjustment (file --> download would download the sheet as the selected type, from context menu use the selection, remove from edit menu)~~ #1934
• ~~Provide feedback language change~~ #1934
• ~~Potentially relocating feedback/docs buttons~~ #1934

All open for debate - expanded convo in Slack