gen-manifests: derrive seedArg from filename and env #16289

Job	Run time
🧹 cloud-cleaner-is-enabled	3s
🔍 Check for missing or unused runner repos	14s
🔍 Check for valid snapshot urls	47s
🗄 DB tests	1m 0s
Gitlab CI trigger helper	5s
⌨ Golang Lint	2m 42s
🎀 kube-linter	19s
📦 Packit config lint	56s
🔍 Check source preparation	1m 16s
🐍 Lint python scripts	1m 12s
📦 RPMlint	1m 18s
🐚 Shellcheck	21s
🛃 Unit tests	3m 39s
	13m 52s

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