Add createdAt and metadata to container, network, and volume resources

[solventak]

Closes #791 , #665

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Add createdAt metadata (generic metadata struct) for each Container, Volume, and Network as well as output in ls commands to display it.

Also fixes a bug when spawning networkvmnet.service where instead of initializing the network configuration from the stored information of NetworkConfiguration entity it would create a new configuration based on key metadata that was passed in through args.

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[solventak]

@jglogan for your consideration :)

[jglogan]

@solventak Sorry, this one fell through the cracks an I didn't get around to reviewing it.

If you're still interested in moving this one forward, please take a look at #1020 as it gives us a more sustainable base for your work.

I'm thinking that our resource types (container, image, volume, network, and possibly others later; for example kernels) in ContainerResource could conform to an Identifiable-conforming ContainerResource protocol along the lines of what you have here. That protocol could have a metadata property that has createdAt and labels.

Let us know here if you're interested in tackling this.