rot13 sub-module makes no sense, please unify with main module

Problem/Motivation

The base obfuscate_module depends on the rot13 sub-module. This makes no sense at all, since that means that under no circumstance is it possible to enable the module without enabling the sub-module.

Steps to reproduce

Enable the module. See that the rot13 is also enabled at the same time.

Proposed resolution

Integrate the sub-module with the main module.

Remaining tasks

• Move the modules/rot13/src/Twig folder to src
• Fix the namespace of src/Twig/Rot13Extension.php to be namespace Drupal\obfuscate_email\Twig;
• Rename the modules/rot13/rot13.services.yml to be obfuscate_email.services.yml
• Fix the class property in obfuscate_email.services.yml to be Drupal\obfuscate_email\Twig\Rot13Extension
• Create a obfuscate_email.install file with an update_hook() function that disables the rot13 module
• Remove the dependency on rot13 from obfuscate_email.info.yml

User interface changes

None

API changes

Namespace of the Twig extension class is changed.

Data model changes

None