shore-config - shore config used to determine renderer/executor

# Description

Original Author: @dkirillov
The `Renderer` and Executor/`Backend` which are part of `Dependencies` should now be determined by the `renderer.type` and `executor.type` found in the shore config.

For this, the shore config will need to be loaded. `PersistentPreRunE` for the root command runs _before_ any of the other commands run, so most likely this would be the places where the shore config is loaded (`LoadShoreConfig` used from #174).

Example shore config:
```yml
renderer:
type: jsonnet

executor:
type: spinnaker
config:
...

profiles:
default:
...
```

This will set the `Renderer` to `jsonnet` and the Executor/`Backend` to `spinnaker` in the `Dependencies`.

Currently, there are only `jsonnet` and `spinnaker` types.

Start at the root command's PersistentPreRunE and the LoadShoreConfig entry point referenced in the issue. Trace how Dependencies currently selects the Renderer and Executor/Backend, then verify that renderer.type and executor.type from the shore config select the existing jsonnet and spinnaker types.

Written by the indexing model from the issue text.