Fix database permissions for localhost connections

[pwtyler]

Summary

• Adds explicit localhost permissions for all three database setup functions
• Fixes connection errors when tests try to connect via localhost
• MySQL/MariaDB treats @'localhost' and @'%' as different host patterns

Problem

The current script only creates users with @'%' permissions, but when tests connect via localhost, they get "Access denied" errors. Encountered when running behat tests on search-replace.

Solution

Added CREATE USER and GRANT statements for @'localhost' in:

• install_mysql_db_8_0_plus()
• install_mysql_db_lower_than_8_0()
• install_mariadb()

Testing

• Tested with MariaDB 11.8
• Verified localhost connections work after running install-package-tests
• Confirmed existing behat tests run

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[pwtyler]

https://mariadb.com/docs/server/mariadb-quickstart-guides/mariadb-connection-troubleshooting-guide#localhost-vs.-wildcard-host-issues

Nevermind, looks like I had a local anonymous user blocking this from working.