Flexible resource limits containers

[redanrd]

Summary

What's changed?

Add cpu limit field when creating/updating a container.

Why do we need this?

Allow users to enter a cpu limit in their serverless configuration file.

How have you tested it?

It is sufficient to uncomment cpu and/or memory in ./examples/container/serverless.yml with chosen valid values as in the README instructions.

cd ./examples/container
serverless deploy

Checklist

• [x] I have reviewed this myself
• [ ] There is a unit test covering every change in this PR
• [x] I have updated the relevant documentation