popular demand: bring back KERNEL_CONFIGURE=yes *during image build*

- partially revert 6ef394d95d (thus bring back the TUI/dialog for selecting KERNEL_CONFIGURE=yes/no)
- partially revert d890b418c7 (thus bring back the capacity to config & build image in one go)
- stop after configuring kernel, but only if command is `kernel-config`, not regular image-build KERNEL_CONFIGURE=yes

lib/functions/artifacts/artifacts-obtain.sh

@@ -280,7 +280,13 @@ function build_artifact_for_image() {
 	# Make sure ORAS tooling is installed before starting.
 	run_tool_oras
 
-	obtain_complete_artifact
+	# Detour: if building kernel, and KERNEL_CONFIGURE=yes, ignore artifact cache.
+	if [[ "${WHAT}" == "kernel" && "${KERNEL_CONFIGURE}" == "yes" ]]; then
+		display_alert "Ignoring artifact cache for kernel" "KERNEL_CONFIGURE=yes" "info"
+		ARTIFACT_IGNORE_CACHE="yes" obtain_complete_artifact
+	else
+		obtain_complete_artifact
+	fi
 
 	return 0
 }