Actions support workflow dispatch event (#28163)

fix #23668 

My plan:
* In the `actions.list` method, if workflow is selected and IsAdmin,
check whether the on event contains `workflow_dispatch`. If so, display
a `Run workflow` button to allow the user to manually trigger the run.
* Providing a form that allows users to select target brach or tag, and
these parameters can be configured in yaml
* Simple form validation, `required` input cannot be empty
* Add a route `/actions/run`, and an `actions.Run` method to handle
* Add `WorkflowDispatchPayload` struct to pass the Webhook event payload
to the runner when triggered, this payload carries the `inputs` values
and other fields, doc: [workflow_dispatch
payload](https://docs.github.com/en/webhooks/webhook-events-and-payloads#workflow_dispatch)

Other PRs
* the `Workflow.WorkflowDispatchConfig()` method still return non-nil
when workflow_dispatch is not defined. I submitted a PR
https://gitea.com/gitea/act/pulls/85 to fix it. Still waiting for them
to process.

Behavior should be same with github, but may cause confusion. Here's a
quick reminder.
*
[Doc](https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_dispatch)
Said: This event will `only` trigger a workflow run if the workflow file
is `on the default branch`.
* If the workflow yaml file only exists in a non-default branch, it
cannot be triggered. (It will not even show up in the workflow list)
* If the same workflow yaml file exists in each branch at the same time,
the version of the default branch is used. Even if `Use workflow from`
selects another branch


![image](4bf596f3-426b-48e8-9b8f-0f6d18defd79)
```yaml
name: Docker Image CI

on:
  workflow_dispatch:
    inputs:
      logLevel:
        description: 'Log level'
        required: true
        default: 'warning'
        type: choice
        options:
        - info
        - warning
        - debug
      tags:
        description: 'Test scenario tags'
        required: false
        type: boolean
      boolean_default_true:
        description: 'Test scenario tags'
        required: true
        type: boolean
        default: true
      boolean_default_false:
        description: 'Test scenario tags'
        required: false
        type: boolean
        default: false
      environment:
        description: 'Environment to run tests against'
        type: environment
        required: true
        default: 'environment values'
      number_required_1:
        description: 'number '
        type: number
        required: true
        default: '100'
      number_required_2:
        description: 'number'
        type: number
        required: true
        default: '100'
      number_required_3:
        description: 'number'
        type: number
        required: true
        default: '100'
      number_1:
        description: 'number'
        type: number
        required: false
      number_2:
        description: 'number'
        type: number
        required: false
      number_3:
        description: 'number'
        type: number
        required: false

env:
  inputs_logLevel:              ${{ inputs.logLevel }}
  inputs_tags:                  ${{ inputs.tags }}
  inputs_boolean_default_true:  ${{ inputs.boolean_default_true }}
  inputs_boolean_default_false: ${{ inputs.boolean_default_false }}
  inputs_environment:           ${{ inputs.environment }}
  inputs_number_1:              ${{ inputs.number_1  }}
  inputs_number_2:              ${{ inputs.number_2  }}
  inputs_number_3:              ${{ inputs.number_3  }}
  inputs_number_required_1:     ${{ inputs.number_required_1  }}
  inputs_number_required_2:     ${{ inputs.number_required_2  }}
  inputs_number_required_3:     ${{ inputs.number_required_3  }}

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - run: ls -la
      - run: env | grep inputs
      - run: echo ${{ inputs.logLevel }}
      - run: echo ${{ inputs.boolean_default_false }}
```

![image](a58a842d-a0ff-4618-bc6d-83a9596d07c8)

![image](44a7cca5-7bd4-42a9-8723-91751a501c88)

---------

Co-authored-by: TKaxv_7S <954067342@qq.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Denys Konovalov <kontakt@denyskon.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/structs/hook.go

@@ -494,3 +494,17 @@ type PackagePayload struct {
 func (p *PackagePayload) JSONPayload() ([]byte, error) {
 	return json.MarshalIndent(p, "", "  ")
 }
+
+// WorkflowDispatchPayload represents a workflow dispatch payload
+type WorkflowDispatchPayload struct {
+	Workflow   string         `json:"workflow"`
+	Ref        string         `json:"ref"`
+	Inputs     map[string]any `json:"inputs"`
+	Repository *Repository    `json:"repository"`
+	Sender     *User          `json:"sender"`
+}
+
+// JSONPayload implements Payload
+func (p *WorkflowDispatchPayload) JSONPayload() ([]byte, error) {
+	return json.MarshalIndent(p, "", "  ")
+}