Generate swagger json (#1402)

- Generate swagger.json into public/
- Add swagger-ui auto-installation
- Add footer link to local swagger-ui
- Add /swagger url for using app url.
- Fix Swagger-UI version via git tag

vendor/code.gitea.io/sdk/gitea/user_key.go

@@ -11,7 +11,12 @@ import (
 	"time"
 )
 
+// PublicKeyList represents a list of PublicKey
+// swagger:response PublicKeyList
+type PublicKeyList []*PublicKey
+
 // PublicKey publickey is a user key to push code to repository
+// swagger:response PublicKey
 type PublicKey struct {
 	ID      int64     `json:"id"`
 	Key     string    `json:"key"`