Add site-config option for preferring private IP addresses over public

[berland]

Network configurations seemingly vary, and it has turned out difficult to programmatically determine which IP address Ert should put into the dispatch_url field in jobs.json. It must be an IP address that is routable from the compute nodes.

It might be sufficient to have a boolean option for whether or not to prefer private IP addresses (for context; see 26203ad8e1377cf10e5420ce3cc4fd3511726273 and #12234).

This is probably a detail too technical to be exposed to users through the config file. It should be possible to use the site-config system for such an option.

[flikka]

With PR https://github.com/equinor/ert/pull/12269 one can choose to prioritize private IP. This can be used to fix this issue.

[jonathan-eq]

#12439