www/nginx site access log rotation

[arichtman]

Important notices

• I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md
• I have searched the existing issues, open and closed, and I'm convinced that mine is new.
• When the request is meant for an existing plugin, I've added its name to the title.

Is your feature request related to a problem? Please describe.

I am using the RAM disk option for logging, under sustained scraper load my site's access log consumes all the available space.

Describe the solution you'd like

System-wide log rotation settings (i.e. under Admin) could rotate and compact the site access (and error) logs.
Alternatively, separate configuration could be done for nginx, but I wouldn't need it myself.

Describe alternatives you've considered

Custom cron job.

Additional context