Issue #3202902 by davidjguru: Reduce naming in routing, classes and permissions

Summary

This Merge Request is gathering changes related with Issue #3202902 , introducing changes in some files:

README.txt
lwm.info.yml
lwm.links.menu.yml
lwm.module
lwm.permissions.yml
lwm.routing.yml
lwm.services.yml
src/Form/LightweightWebformMailchimpAdminSettingsForm.php -> src/Form/LwmAdminSettings.php
src/Services/LightweightWebformMailchimpClient.php -> src/Services/LwmClient.php

Epic

This merge request owns to Epic #3200222 : [Epic] Improve data and metadata about the module.
Parent Issue: https://www.drupal.org/project/lwm/issues/3200222

This set of commits

1. Renames the module's naming in Form, Service, .yml files and config values.

For testing

Downloand, install and check the normal functioning.