Default environment values in Carvel or being discarded when any environment is provided by user

[corneil]

Problem description:
The default values for the kubernetes environment are discarded when a user provides a value for environmentVariables.

Solution description:
Since the value is a single property in YAML and a comma separated list of key=value pairs the user provided value overrides the defaults.
The solution is to provide a separate property for user provided environment variables that can be appended to the default environment and then assign to the property.