This issue is part of the course hierarchy project (also known as "long-term").

The goal of this task is to create a sub plugin called mod_subsection so it can be used during the projects.

The goals are:

• The phase 2 of the project will introduce delegated sections. This new section type will depend on a plugin to work, but no plugin will be added to the core yet. The plugin created in this task can be used in the testing instructions so the Phase 2 issues can be integrated into the core.
• The plugin will be kept updated with all the delegated section integrations appearing as part of the project.
• In phase 3, this plugin will be used as a base for the real mod_subsection added to the core. This will be the first plugin to use delegated sections.

What needs to be done:

• The plugin will be mod_subsection
• Create a base plugin. The plugin will be an essential hello world activity.
• The plugin must be hosted in a GitHub public repository so all devs in the project can do pull requests when new delegated sections appear.
• The plugin must have backup and restore because this is an essential integration.
• Internally, it must follow the conventions introduced in all new core activities. For example, it must have a "mod_subsection\manager" class similar to the one in mod_data.