Output log with JSON format in default

[crazytaxii]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Print log with JSON format in default for log collection, and it can be set by config file also:

default:
  log_format: json # or 'text'

Now support 2 log format:

1. json (default)

   {"client_ip":"127.0.0.1","latency":"639µs","level":"info","method":"GET","msg":"SUCCESS","request_id":"20240415121305-030470","status_code":200,"time":"2024-04-15T12:13:05.383647879-04:00","uri":"/pixiu/tenants/1"}
   

2. text (optional)

   INFO[2024-04-15T12:15:08.199096253-04:00] SUCCESS                                       client_ip=127.0.0.1 latency="755µs" method=GET request_id=20240415121508-615041 status_code=200 uri=/pixiu/tenants/1
   

Does this PR introduce a user-facing change?

NONE

[caoyingjunz]

lgtm，thanks