Add validation of configuration values from the tembo.toml file

[nhudson]

This change will add configuration validation against the temboclient for the following items. The validation will fail if the client cannot validate the values.

• environment
• cpu
• memory
• replicas
• storage
• stack types

Added tests using a crate called rstest that allows you to easily add macros for fixture based tests. If someone would rather me write all the test scenarios out instead I can, just comment and let me know.

[shahadarsh]

LGTM 👍

Thanks for doing this. The tests are failing because it says CPU value is invalid for one of the tests but I think its a valid value. I can take a look at it later. I might have to generate the rust client again with latest values.