Hi Cockpit developers,

I saw that on cockpit-209 Session timeouts were added with the default to 15 minutes of inactivity (https://cockpit-project.org/blog/cockpit-209.html).
I think that this change is problematic because:
1. The timeout is very short and it can cause unexpected behavior to users and cockpit packages.
2. The timeout can only be configured in the /etc/cockpit.conf file, so it is hard for packages to configure it to fit to their behavior.

For example,
we created a package for installing ovirt with cockpit UI, that installation can take a lot of time, it has different phases and logging out in the middle can cause problems.
We prefer to avoid editing /etc/cockpit.conf because we don't want to run over user configuration (what to do when there is already cockpit.conf present?) 

I want to suggest:
1. Raising the timeout to 2 hours of inactivity, this seems reasonable.
2. Provide a more flexible way of configuring the timeout, with an option to the manifest.json package file and/or with a cockpit API call.