Allow usage of local eav-attribute-groups.xml file

[treestonemedia]

Preconditions

1. Setup a custom module for the migration as recommended by Magento here

Steps to reproduce

1. Setup a custom module for the migration
2. In your config.xml file, point eav_attribute_groups_file to a file in <your Magento 2 install dir>/app/code/Vendor/Migration/etc/.../eav_attribute_groups.xml
3. Run the migration
4. bin/magento migrate:data app/code/Vendor/Migration/etc/.../config.xml

Expected result

1. The migration should run with the values from our own eav_attribute_groups.xml file

Actual result

1. The migration tool tries loading the eav_attribute_groups.xml file from the root of the vendor/magento/data-migration-tool and it throws an error that the file isn't found.
2. `In Groups.php line 54:

Invalid groups filename: /var/www/html/vendor/magento/data-migration-tool/app/code/{vendor}/Migration/etc/opensource-to-opensource/1.7.0.2/eav-attribute-groups.xml`

Additional notes

1. If you copy your eav-attribute-groups.xml into vendor/magento/data-migration-tool/...` it will work just fine
2. Ideally we should never be touching anything in the vendor directory and all customization and configuration should be done at the local module level
3. The map file does support using one in your local module directory
4. It would be great to have the same type of support for the eav-attribute-groups.xml file

[victor-v-rad]

Hi @treestonemedia

Thank you for good described issue and the PR. MC-30388 was created to process it.