Upgrade to Java 21, Java 17 is EOL

[al-niessner]

Checked for duplicates

No - I haven't checked

🧑‍🔬 User Persona(s)

upgrade to java 21

💪 Motivation

java 17 no longer receives patches from Oracle without payment in 1 month. https://endoflife.date/oracle-jdk

⚙️ Engineering Details

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🎉 I&T

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