Fixes / improvements related to logger

[lipaun]

• Fixed permissions when triggering logrotate or logreopen (logto and logger plugin).
• log-backupname option now accepts strftime formatting specifiers.
• New config option "cron-logrotate", which will use internal cron to trigger log rotation

Examples (using ini file):

Will trigger log rotation every day and rotated file will be like: logfile.2024-08-22.log

logto = logfile.log
log-backupname = logfile.%%Y-%%m-%%d.log
cron-logrotate = 59 23 -1 -1 -1

Will log to both stdout and file, will trigger log rotation every day and rotated file will be like: logname.2024-08-22.log

logger = stdio
logger = file:logfile=logname.log,backupname=logname.%%Y-%%m-%%d.log,cron=59 23 -1 -1 -1