Migrate CCP plugin to Freva plugin template

Benefits of Migrating This Plugin to the Freva-Plugin-Template

• Enables testing to verify if the plugin works correctly with the prepared examples. see Functional testing reuslt.

• Automatically generate API references and comprehensive documentation. See Documentation.

• Get access to unit testing directly from the source. Coverage report.

• The repository becomes more organized and readable.

• Maintains coding standards through linting.

• Adds the license in a standardized manner.

Since we have not changed anything in the source code and have only migrated the main version of the code, this can be immediately merged. However, since this is the first plugin we are migrating, a double-check is necessary to ensure there are no issues before moving it to production.

The issues #2 (closed) and #4 are still left which we need to take care of them in another MR.

Close #3 (closed)