[workchat] prepare the workflow framework (#218138)

## Summary

Setup the foundations of the workflow framework, adding types and
initial implementation.


## Examples

### Looping over some input to call the LLM

**workflow**
```typescript
{
      id: 'my_test_workflow',
      name: 'Just a test workflow',
      type: 'graph',
      inputs: [
        {
          name: 'input',
          type: 'array',
          required: true,
        },
      ],
      steps: [
        {
          id: 'mainLoop',
          type: NodeType.loop,
          configuration: {
            inputList: 'input',
            itemVar: 'prompt',
            output: {
              source: 'output',
              destination: 'results',
            },
            steps: [
              {
                id: 'step1',
                type: NodeType.prompt,
                configuration: {
                  prompt:
                    'How much is {prompt}? Please just output the result without anything else',
                  output: 'output',
                },
              },
            ],
          },
        },
      ],
      outputs: [
        {
          name: 'results',
          ref: 'results',
        },
      ],
    }
``` 

**Running**
```ts
workchatFramework.workflows.run({
    id: 'my_test_workflow',
    inputs: { input: ['3 + 3', '7 - 1', '4 * 6'] },
    request,
})
```

**Output**

```ts
 {
  runId: '6f254746-57fc-4fd3-8bfa-25014725f53f',
  output: { results: [ '6', '6', '24' ] }
}
```

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

packages/kbn-check-mappings-update-cli/current_fields.json

@@ -819,6 +819,13 @@
     "state",
     "type"
   ],
+  "onechat_workflow": [
+    "access_control",
+    "access_control.public",
+    "categories",
+    "user_id",
+    "workflow_id"
+  ],
   "osquery-manager-usage-metric": [
     "count",
     "errors"

packages/kbn-check-mappings-update-cli/current_mappings.json

@@ -2749,6 +2749,27 @@
       }
     }
   },
+  "onechat_workflow": {
+    "dynamic": false,
+    "properties": {
+      "access_control": {
+        "properties": {
+          "public": {
+            "type": "boolean"
+          }
+        }
+      },
+      "categories": {
+        "type": "keyword"
+      },
+      "user_id": {
+        "type": "keyword"
+      },
+      "workflow_id": {
+        "type": "keyword"
+      }
+    }
+  },
   "osquery-manager-usage-metric": {
     "properties": {
       "count": {

packages/kbn-optimizer/limits.yml

@@ -195,3 +195,4 @@ pageLoadAssetSize:
   wciIndexSource: 40000
   wciSalesforce: 25000
   workchatApp: 25000
+  workchatFramework: 25000