docs: document JVM heap sizing #248

Job	Run time
Detect relevant changed files	6s
Build/Publish ${{ matrix.runner.arch }} Image	-1s
Run cargo-udeps	-1s
Generate Provenance for (oci.stackable.tech)	-1s
Publish/Sign ${{ needs.build-container-image.outputs.operator-version }} Index	-1s
Package/Publish ${{ needs.build-container-image.outputs.operator-version }} Helm Chart	-1s
Generate Provenance for (quay.io)	-1s
Run OpenShift Preflight Check for ${{ needs.build-container-image.outputs.operator-version }}-${{ matrix.arch }}	-1s
Failure Notification	0s
Finished Build and Publish	0s
	-1s

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