cannet v0.8.1

• introduce themes, including light, default remains dark
• additional logging and status messages for python sidecar, including its own log file
• add connection status indicator to logical bus in project panel
• extract base gridview control
  • used for:
    • trace (by-id and historical)
    • transmit
    • signals
    • dbc
    • rbs
  • commonizes scroll behaviors, keyboard nav, and multiselection for these views (actually fixes historical trace scroll-while-message-expanded bug)