Rebase Tor Browser esr68 patches on top of esr78

• #31918 (closed)
• #33734 (closed)
• #33737 (closed)
• #33856 (closed)
• #33862 (closed)
• #33890 (closed)
• torbutton#33892 (closed)
• #34145 (closed)
• #34209 (closed)
• #40010 (closed)
• #40022 (closed)
• #40025 (closed)
• #40035 (closed)
• #40036 (closed)
• #40037 (closed)
• #40039 (closed)
• #40040 (closed)
• #40041 (closed)
• #40074 (closed)
• #40076 (closed)