Add dry-run before applying manifests

[windsource]

Description

When calling ank apply there are different possible actions for each workload in the manifests that would have been passed.

1. No action for that workload: The workload has not been changed and as such no action for this workload will be executed.
2. Workload will be created: The workload did not exist so far and will be created.
3. Workload will be deleted and created again: The workload exists already but the new manifest contains a change (e.g. in the runtime config) that requires the workload to be deleted and created again such that the change get effective.
4. Workload will be deleted

When there are a lot of workloads already running it might not be obvious for the user which action will be applied for each workload. For this a --dry-run option might be useful.

Probably the dry run needs to be executed by the server. I am not sure if the CLI could also perform a dry run without involving the server.

In addition this dry-run might also be executed by a workload for example in a web based dashboard.

Goals

Add a dry run functionality to the control interface and CLI.

Final result

Summary

To be filled when the final solution is sketched.

Tasks

• Task 1
• Task 2
• ...

[windsource]

We should also have a dry run for ank set state.