Support scoped access tokens (#20908)

This PR adds the support for scopes of access tokens, mimicking the
design of GitHub OAuth scopes.

The changes of the core logic are in `models/auth` that `AccessToken`
struct will have a `Scope` field. The normalized (no duplication of
scope), comma-separated scope string will be stored in `access_token`
table in the database.
In `services/auth`, the scope will be stored in context, which will be
used by `reqToken` middleware in API calls. Only OAuth2 tokens will have
granular token scopes, while others like BasicAuth will default to scope
`all`.
A large amount of work happens in `routers/api/v1/api.go` and the
corresponding `tests/integration` tests, that is adding necessary scopes
to each of the API calls as they fit.


- [x] Add `Scope` field to `AccessToken`
- [x] Add access control to all API endpoints
- [x] Update frontend & backend for when creating tokens
- [x] Add a database migration for `scope` column (enable 'all' access
to past tokens)

I'm aiming to complete it before Gitea 1.19 release.

Fixes #4300

services/forms/user_form.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"strings"
 
+	auth_model "code.gitea.io/gitea/models/auth"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/structs"
@@ -377,7 +378,8 @@ func (f *AddSecretForm) Validate(req *http.Request, errs binding.Errors) binding
 
 // NewAccessTokenForm form for creating access token
 type NewAccessTokenForm struct {
-	Name string `binding:"Required;MaxSize(255)"`
+	Name  string `binding:"Required;MaxSize(255)"`
+	Scope []string
 }
 
 // Validate validates the fields
@@ -386,6 +388,12 @@ func (f *NewAccessTokenForm) Validate(req *http.Request, errs binding.Errors) bi
 	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
 }
 
+func (f *NewAccessTokenForm) GetScope() (auth_model.AccessTokenScope, error) {
+	scope := strings.Join(f.Scope, ",")
+	s, err := auth_model.AccessTokenScope(scope).Normalize()
+	return s, err
+}
+
 // EditOAuth2ApplicationForm form for editing oauth2 applications
 type EditOAuth2ApplicationForm struct {
 	Name               string `binding:"Required;MaxSize(255)" form:"application_name"`