feat: manage bot accounts from the admin UI, API and CLI (#38966)

Adds first-class bot accounts (`UserTypeBot`): local, password-less
users for automation that authenticate only with access tokens.

1. Admin UI: create bots, filter users by type, manage a bot's access
tokens, convert between user and bot
2. API: `POST /admin/users/{username}/convert-type`, and user objects
gain a GitHub-compatible `type` (`User`, `Organization`, `Bot`)
3. CLI: `gitea admin user change-type`, `--user-type` accepts `User` or
`Bot` case-insensitively
4. Converting keeps the password, 2FA, OAuth2 grants and access tokens,
and since sign-in rejects bots, converting back restores the account.
Only local, non-admin accounts can be converted, and conversions are
audited
5. Session, reverse proxy, SSPI, external source and password reset
sign-in reject non-individual users, so a bot never gets an interactive
session
6. Bots receive no notifications or emails

Co-authored-by: Nicolas <bircni@icloud.com>
Co-authored-by: joestump <joe@joestump.net>
Co-authored-by: Joe Stump <joe@stu.mp>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/templates/util_misc.go

@@ -16,6 +16,7 @@ import (
 	repo_model "gitea.dev/models/repo"
 	user_model "gitea.dev/models/user"
 	"gitea.dev/modules/git"
+	"gitea.dev/modules/htmlutil"
 	"gitea.dev/modules/json"
 	"gitea.dev/modules/log"
 	"gitea.dev/modules/repository"
@@ -168,6 +169,14 @@ func mirrorRemoteAddress(ctx context.Context, m *repo_model.Repository, remoteNa
 	return ret
 }
 
+// UserTypeLabel marks a bot account next to a name built in Go, the template equivalent is shared/user/user_type_label
+func (ut *RenderUtils) UserTypeLabel(u *user_model.User) template.HTML {
+	if u == nil || !u.IsTypeBot() {
+		return ""
+	}
+	return htmlutil.HTMLFormat(` <span class="ui basic label tw-py-0 tw-align-baseline">%s</span>`, ut.locale().TrString("concept_user_bot"))
+}
+
 func filenameIsImage(filename string) bool {
 	mimeType := mime.TypeByExtension(filepath.Ext(filename))
 	return strings.HasPrefix(mimeType, "image/")