Add extension description #325

Job	Run time
CI Sanity Check	31s
Initial JDK 17 Build	12m 59s
Attach pull request number	0s
Calculate Test Jobs	8s
Kubernetes Tests - JDK ${{ matrix.java.name }}	0s
Devtools Tests - JDK ${{ matrix.java.name }}	0s
Gradle Tests - JDK ${{ matrix.java.name }}	0s
JVM Tests - JDK 17	9m 27s
JVM Tests - JDK 21	7m 55s
Maven Tests - JDK ${{ matrix.java.name }}	0s
JVM Tests - JDK 17 Windows	10m 4s
Native Tests - ${{ matrix.category }}	0s
Quickstarts Compilation - JDK 17	6m 14s
MicroProfile TCKs Tests	0s
Native Tests - Virtual Thread - ${{ matrix.category }}	0s
Upload build stats to collector	0s
Build report	32s
	47m 50s

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