Allow to configure Services

[bohdan-shulha]

Add a new page - "Services" (on the PoC stage - Service of the Stack Template).

The form should have multiple steps:

1. Select either "start from scratch" (e.g. with my own registry/image/etc).
2. Use the Service Template (click on a tile to pre-fill all the mandatory fields).

The concept of "Stacks" or "Apps" or whatever else will be created later, once it become clear, what are the actual requirements to this domain entity.

[bohdan-shulha]

Seems to work fine.