The Linux services should have KeyPair parameter in WebUI

Need to add the ability to configure Key Pair for all Linux-based Murano services (like Telnet service and Apache service and etc.)
User should have the ability to select one Key Pair for this service and this key pair should be assigned to the VM with Linux-based service.

User Story #1:
I'm user and I want to create and deploy Linux Telnet service using Murano Web UI.
I'm login to Murano Web UI, create environment and click to Create Service in this environment.
After that I have to select the type of the service 'Linux Telnet' and click Next.
On the next page of the wizard form I should see the drop-down list with the Key Pairs (which I'm use in my tenant) and I can select one Key Pair for this service. Also I have to set other parameters and click Create.
When new service created, I can click on 'Deploy This Environment' button and after a few minutes I should have successfully deployed VM with telnet service and my Key Pair should be assigned to this VM and I should have the SSH access to this VM with my Key Pair.