feat: implement a method to delete a directory from a template.

[GiantTreeLP]

Motivation

See #1198.

Modification

This change allows developers to directly delete a directory and all its containing files and directories from a given service template.

As an additional functionality, this method is also exposed to the HTTP Rest API much like the file deletion method already is.

Result

Developers can now delete entire directory trees from a given template.

Other context

Closes #1198.

Local template storage has already been tested on my machine, I will check whether SFTP and S3 storage can be tested. If not, I may seek help from your end.