Add initial `spack.yaml` and `config` #4

Job	Run time
Closed	0s
Comment	0s
CI / Set Defaults	1s
CI / Validate JSON / Setup Validate JSON	5s
CI / Check spack.yaml	7s
CI / Validate JSON / Validate (versions)	4s
CI / Get Version and Tag Prerelease	0s
CI / Check Config Fields	0s
CI / Notifier	0s
CI / Deploy to Prerelease	0s
	17s

Provide feedback