Have PRIORITIZE_PRIVATE_IP_ADDRESS available only via site config

[jonathan-eq]

Issue
Resolves #12601

Approach
Short description of the approach

(Screenshot of new behavior in GUI if applicable)

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'just rapid-tests')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Add backport label to latest release (format: 'backport release-branch-name')

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.65%. Comparing base (f0d9de4) to head (04fcd90).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12614      +/-   ##
==========================================
- Coverage   90.68%   90.65%   -0.03%     
==========================================
  Files         429      429              
  Lines       29808    29799       -9     
==========================================
- Hits        27030    27015      -15     
- Misses       2778     2784       +6     

Flag	Coverage Δ
cli-tests	37.55% <ø> (-0.01%)	⬇️
gui-tests	69.37% <ø> (+0.01%)	⬆️
performance-and-unit-tests	73.92% <ø> (-0.01%)	⬇️
test	38.07% <ø> (+<0.01%)	⬆️

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[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing jonathan-eq:fix-private-ip-address (04fcd90) with main (f0d9de4)}

Summary

✅ 22 untouched benchmarks

[xjules]

I'd reword this by emphasizing that some global options can be additionally configured by this. I'll leave the exact formulation to you :)

[jonathan-eq]

How about Ert can have some global options set by plugins through the `ert.plugins.hook_specifications.site_config.site_configurations` hook.

[xjules]

not sure, if this convey the info properly. The point is that these are defaults. But prioritize can be set only via site-config.