fix: code refactoring and namespace/use statements.

[julianramirez2]

Description

A refactoring of the code was done in order to decouple the code from the Openedx_Woocommerce_Plugin_Admin file for:

• Facilitate future implementations
• Facilitate the testing process of the class.

In addition, namespace and their respective "use" were declared if necessary in each class in order to make easier and cleaner the invocation of the classes between the plugin files. It will benefit us as developers for a better understanding and improve the scalability of the code.

Testing instructions

To test, perform the normal flow of activation and deactivation of the plugin and make the flow of an "Enrollment Request" in the dashboard (with the functionalities that we have so far) to check that there is no invocation to an existing class that cannot be found because of the namespace statements.

Checklist for Merge

• Tested in a remote environment
• Rebased master/main
• Squashed commits

[MaferMazu]

This looks good to me. I would like @jvegalo opinion, and if he thinks that it is okay and doesn't have improvement comments, you can squash and merge.