allow custom args & config in devnet setup with `custom-` prefix #187

Job	Run time
Run code checks / Run code checks	36s
Generate project documentation	4s
Build Assertoor / Build linux/arm64 binary	2m 36s
Build Assertoor / Build linux/amd64 binary	27s
Build Assertoor / Build macos/amd64 binary	3m 33s
Build Assertoor / Build macos/arm64 binary	1m 12s
Build Assertoor / Build windows/amd64 binary	4m 48s
Build Assertoor / Build amd64 docker image	35s
Build Assertoor / Build arm64 docker image	2m 3s
Build Assertoor / Build multiarch docker image	1s
Build Assertoor / Build additional docker manifests	1s
Create snapshot release	1s
	15m 57s

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