More enhancement for Riofile

[StrongMonkey]

• Add rio stack in CLI. Stack will be the API backend support what Riofile defines. Should be able to do edit, inspect and rm on stacks.
• rio edit should support Riofile format.
• rio export should support Riofile format.

[StrongMonkey]

Available to test in v0.4.0-rc1:
Introducing Stack concept: Stack represents one Riofile.
To create a stack, run rio up.(currently Directory should have Riofile)
To create a stack based on a specific file, run rio up -f $file
To create a stack based on a remote file, run rio up -f http:/file
To create a stack to watch a git repo, run rio up https://git-repo.git. (Push any changes to this repo, it should automatically watch and refresh)

rio edit will have the pretty edit format by default.
rio export will have both pretty and raw k8s format. Use --stack to switch.

[tfiduccia]

Version - v0.4.0-rc2
Verified all three formats for up.