No "Drupal" in UI text -- migrate, migrate_drupal, migrate_drupal_ui

Problem/Motivation

This is a child issue of 📌 [meta] Replace Drupal in UI text with the name of the distribution Active , for the following modules/components: migrate, migrate_drupal, migrate_drupal_ui.

Drupal has a deal with distributions, that they can replace Drupal with their own Distribution name. Also we have a UI text standard
https://www.drupal.org/docs/develop/user-interface-standards/interface-t... →
that says:

Use "Site"—not "Drupal". Referring to Drupal by name complicates distributions, and users may not know the site is running on Drupal.

You can also use terms like "the core software".

But Drupal still appears in the UI.

Proposed resolution

Replace Drupal in UI text with the distribution name, or phrases like "the site" and "the core software".

Remaining tasks

1. Novice task -- Locate the word "Drupal" appearing in UI text in this group of modules/themes. Here's a grep command that yields some false positives, but should find most/all of what we're looking for:
   

   egrep -i -e "'[^']*[^/\]drupal[^/\]" -e '"[^"]*[^/\]drupal[^/\]' `find . \( -type d -name tests \) -prune -o -type f -print` | grep -i --color drupal
   

2. Novice task -- Replace each occurence either with "the core software", "the site", or the distribution name. There is a function that will return the distribution name: drupal_install_profile_distribution_name().
3. Novice task -- Make and upload a patch file, or use an issue fork / merge request workflow.

User interface changes

We will not use the word Drupal in the UI, but instead either show the distribution name or the phrases "the site" or "the core software".

API changes

None.

Data model changes

None.

Release notes snippet

Not necessary.