logging: Reduce verbosity of common FTP commands
logging: Reduce verbosity of common FTP commands

Remove/reduce verbosity of:

- Clients trying to CWD to a (non-existing) file/dir
- Old development debugging
- RETR non-existing files
- Upload/Download of files LOG --> INFO

Signed-off-by: Joachim Nilsson <583c295fd7602c168ad814279bbc3894ba65f5d6@gmail.com>

troglobit/uftpd,troglobit/uftpd