XFCE :- Major changes and bug fixes

[Akash6222]

• Check welcome dark mode option working fine or not
• Qogir theme fix icon not showing and remove mountain bg
• Remove unwanted qogir theme from Appearance list
• Enable set matching xfwm4 theme #Changed Qogir-dark to Qogir-Dark alg-xfce-settings#2
• Terminal colour (enable use system theme) and Font (enable use system font)
• Increase panel icon size
• Replace neofetch with fastfetch
• Add clipboard plugin on panel
• Disable save session on logout
• Fix terminal default geometry to align