Glances as system tool is often executed in a multi-user environment or
even with root privileges. Then, make the log file system-aware as well.

See 8866321a.

This reverts commit 4877be45.

Configure server cache time from the command line (--cached-time) #901 / Also implement cache time for the Web server mode

As per [their blog post of the 27th April](https://blog.readthedocs.com/securing-subdomains/) ‘Securing subdomains’:

> Starting today, Read the Docs will start hosting projects from subdomains on the domain readthedocs.io, instead of on readthedocs.org. This change addresses some security concerns around site cookies while hosting user generated data on the same domain as our dashboard.

Test Plan: Manually visited all the links I’ve modified.