Add support for workflow_dispatch (#3334)

Closes #2797

I'm aware of https://github.com/go-gitea/gitea/pull/28163 exists, but since I had it laying around on my drive and collecting dust, I might as well open a PR for it if anyone wants the feature a bit sooner than waiting for upstream to release it or to be a forgejo "native" implementation.

This PR Contains:
- Support for the `workflow_dispatch` trigger
- Inputs: boolean, string, number, choice

Things still to be done:
- [x] API Endpoint `/api/v1/<org>/<repo>/actions/workflows/<workflow id>/dispatches`
- ~~Fixing some UI bugs I had no time figuring out, like why dropdown/choice inputs's menu's behave weirdly~~ Unrelated visual bug with dropdowns inside dropdowns
- [x] Fix bug where opening the branch selection submits the form
- [x] Limit on inputs to render/process

Things not in this PR:
- Inputs: environment (First need support for environments in forgejo)

Things needed to test this:
- A patch for https://code.forgejo.org/forgejo/runner to actually consider the inputs inside the workflow.
  ~~One possible patch can be seen here: https://code.forgejo.org/Mai-Lapyst/runner/src/branch/support-workflow-inputs~~
  [PR](https://code.forgejo.org/forgejo/runner/pulls/199)

![image](/attachments/2db50c9e-898f-41cb-b698-43edeefd2573)

## Testing

- Checkout PR
- Setup new development runner with [this PR](https://code.forgejo.org/forgejo/runner/pulls/199)
- Create a repo with a workflow (see below)
- Go to the actions tab, select the workflow and see the notice as in the screenshot above
- Use the button + dropdown to run the workflow
  - Try also running it via the api using the `` endpoint
- ...
- Profit!

<details>
<summary>Example workflow</summary>

```yaml
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
      number1_default:
        description: 'Number w. default'
        default: '100'
        type: number
      number2:
        description: 'Number w/o. default'
        type: number
      string1_default:
        description: 'String w. default'
        default: 'Hello world'
        type: string
      string2:
        description: 'String w/o. default'
        required: true
        type: string

jobs:
  test:
    runs-on: docker
    steps:
      - uses: actions/checkout@v3
      - run: whoami
      - run: cat /etc/issue
      - run: uname -a
      - run: date
      - run: echo ${{ inputs.logLevel }}
      - run: echo ${{ inputs.tags }}
      - env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        run: echo "$GITHUB_CONTEXT"
      - run: echo "abc"
```
</details>

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/3334
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Mai-Lapyst <mai-lapyst@noreply.codeberg.org>
Co-committed-by: Mai-Lapyst <mai-lapyst@noreply.codeberg.org>

tests/integration/actions_trigger_test.go

@@ -396,3 +396,46 @@ func TestCreateDeleteRefEvent(t *testing.T) {
 		assert.NotNil(t, run)
 	})
 }
+
+func TestWorkflowDispatchEvent(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+		// create the repo
+		repo, sha, f := CreateDeclarativeRepo(t, user2, "repo-workflow-dispatch",
+			[]unit_model.Type{unit_model.TypeActions}, nil,
+			[]*files_service.ChangeRepoFile{
+				{
+					Operation: "create",
+					TreePath:  ".gitea/workflows/dispatch.yml",
+					ContentReader: strings.NewReader(
+						"name: test\n" +
+							"on: [workflow_dispatch]\n" +
+							"jobs:\n" +
+							"  test:\n" +
+							"    runs-on: ubuntu-latest\n" +
+							"    steps:\n" +
+							"      - run: echo helloworld\n",
+					),
+				},
+			},
+		)
+		defer f()
+
+		gitRepo, err := gitrepo.OpenRepository(db.DefaultContext, repo)
+		assert.NoError(t, err)
+		defer gitRepo.Close()
+
+		workflow, err := actions_service.GetWorkflowFromCommit(gitRepo, sha, "dispatch.yml")
+		assert.NoError(t, err)
+
+		inputGetter := func(key string) string {
+			return ""
+		}
+
+		err = workflow.Dispatch(db.DefaultContext, inputGetter, repo, user2)
+		assert.NoError(t, err)
+
+		assert.Equal(t, 1, unittest.GetCount(t, &actions_model.ActionRun{RepoID: repo.ID}))
+	})
+}