Add GRPC + Rest endpoint to retreive VM Config, Inject and Inherit Secrets and Configmaps to environment config

[jggoebel]

What this PR does / why we need it:
Retreives the current VM Configuration for a given VM via a gRPC endpoint.
Needed by controllers, currently the terraform controller calculates the config themselves

VM Controller injects secret in fields where the value is
inject_secret:<name>:<field>
The same is applied for configmaps:
inject_configmap:<name>:<field>
This ensures that no secrets are stored directly inside the environment enabling us to store environments inside a git repository.

Also whole secrets and configmap data can be inherited by using
inherit_secrets as the key and a comma sepperated list with secret metadata.names
Same applies to inherit_configmaps for configmaps
Example
inherit_secrets = secret1,secret2 will inherit data from secret1 and secret2. So if secret1 has a field token with the value abc it will be added to the config

Also adds a REST endpoint in order to retreive VM configuration inside the admin ui in order to debug VMs

Before this PR the controller itself retreives the environment and checks if the given VMT is enabled on the environment.
This PR moves this behaviour to the VM creation, so that controllers do not have to check if this is a valid configuration.

Which issue(s) this PR fixes: