Add a banner

[chenquan]

Add a banner for go-zero and print at startup.
example:

________  ________               ________  _______   ________  ________     
|\   ____\|\   __  \             |\_____  \|\  ___ \ |\   __  \|\   __  \    
\ \  \___|\ \  \|\  \  ___________\|___/  /\ \   __/|\ \  \|\  \ \  \|\  \   
 \ \  \  __\ \  \\\  \|\____________\ /  / /\ \  \_|/_\ \   _  _\ \  \\\  \  
  \ \  \|\  \ \  \\\  \|____________|/  /_/__\ \  \_|\ \ \  \\  \\ \  \\\  \ 
   \ \_______\ \_______\            |\________\ \_______\ \__\\ _\\ \_______\
    \|_______|\|_______|             \|_______|\|_______|\|__|\|__|\|_______|

[kevwan]

Good suggestion! But if print this, this kind of messages will be collected incorrectly?

[chenquan]

Use fmt.Println print, And filter it.