This method creates a folder for templates in the project and returns it with the same fields as Get the list of folders.
The returned id can be passed as folderId to Create a template from MJML, Create or overwrite a template from HTML, Copy templates into a folder and Move templates into a folder.
The folder appears in the project in Stripo right away. It has no author, the same as templates created through the API.

Folder name rules:

• up to 100 characters;
• must not contain [ ] { } $ < >;
• if a template folder with the same name already exists in the project, a number is added (e.g. Offers 2); the response contains the actual name.

The number of folders in a project is limited, the same as in Stripo.