MVP-144: Modified default for COOKIE_DOMAIN

[BradyMitch]

🎯 Summary

MVP-144

Sets the default value for COOKIE_DOMAIN to localhost if FRONTEND_URL includes localhost, otherwise it sets to .gov.bc.ca

• Updated Wiki Env vars

🔰 Checklist

• I have read and agree with the following checklist and am following the guidelines in our Code of Conduct document.

• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation where required.
• I have tested my changes to the best of my ability.
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