Introduce waiting status in /sequence endpoint

[ermin-muratovic]

The /sequence endpoint returns a state property and each stage has also a state property. Currently the overall state might be triggered, paused or finished. However, the stage state is either triggered or finished, see example below.
The state value should also return started for started stages.

{
  "name": "delivery",
  "service": "carts",
  "project": "sockshop",
  "time": "2021-10-06T09:28:50.796Z",
  "shkeptncontext": "ae02c298-e6ab-4453-87c6-492eea4fdca9",
  "state": "paused",
  "stages": [
    {
      "name": "dev",
      "image": "docker.io/keptnexamples/carts:0.12.1",
      "state": "triggered",
      "latestEvent": {
        "type": "sh.keptn.event.test.triggered",
        "id": "ba87752d-3a99-4388-84b0-08f988322a9a",
        "time": "2021-10-06T09:30:19.744Z"
      }
    }
  ]
}'

If the user paused a sequence, I would expect to see the state paused instead of the state triggered.
If the sequence is waiting for another sequence to be finished, I would expect to see the state waiting instead of the state triggered.

This is a breaking change.

DoD

• Unit tests
• Integration tests

[thisthat]

We should define the list of possible states before we can tackle this issue

[odubajDT]

@thisthat is the list of possible states already defined for this issue ? Thank you.

[odubajDT]

From discussion we know that states of sequences can have these values:

• triggered
• started
• finished
• paused
• timedOut
• aborted

Stages have also the same states as sequences + state succeeded

It should be enough to introduce a new state waiting to cover when the sequence is waiting for a condition (f. e. another sequence).

Use Case

When a running sequence (in state started) needs to wait, it changes its state to waiting. The same happens to each stage which is currently running (has state started)