Add ability to check for email templates

[subbu1993]

Adds ability to check for email template overrides

The idea here is that most merchants use custom email templates, so the default order_new_guest.html file from magento is almost always modified

magento records the OG template information in the email_template table, we use that information to identify if the merchant has a modified email template and flag it when the OG template was modified in Magento

The only requirement here is that the devs should sync the email_template table to their local before running the helper

app@31fb81ebf1b1:~/html$ php bin/magento sd:dev:upgrade-helper 2-3-3-to-2-3-3-p1.diff
Populating file override index...
Lines in diff processed: 92152/92152 [============================] 100% (elapsed: < 1 sec | remaining: ~< 1 sec)
-------- preferences --------
Patched: vendor/magento/module-catalog-search/Model/ResourceModel/Fulltext/Collection.php
Customized: SomethingDigital\AjaxLayeredNav\Model\ResourceModel\CatalogSearch\Fulltext\Collection\Interceptor
-------- overrides --------
Patched: vendor/magento/module-review/view/frontend/templates/review.phtml
Customized: vendor/dotmailer/dotmailer-magento2-extension/view/frontend/templates/email/review.phtml
Customized: vendor/paypal/module-braintree-core/view/frontend/templates/googlepay/review.phtml
Customized: app/code/WeltPixel/GoogleCards/view/frontend/templates/product/view/review.phtml
Patched: vendor/magento/module-sales/view/frontend/email/shipment_new.html
Customized: app/design/frontend/Vendor/default/Magento_Sales/email/shipment_new.html
Patched: vendor/magento/module-sales/view/frontend/email/shipment_new_guest.html
Customized: app/design/frontend/Vendor/default/Magento_Sales/email/shipment_new_guest.html
Patched: vendor/magento/module-staging/view/adminhtml/templates/preview.phtml
Customized: vendor/dotmailer/dotmailer-magento2-extension/view/adminhtml/templates/system/preview.phtml
-------- email_template --------
Patched: vendor/magento/module-email/view/frontend/email/header.html
Customized: Vendor Email Header
Patched: vendor/magento/module-gift-card/view/frontend/email/gift_information.html
Customized: Free Gift Card with Purchase
Patched: vendor/magento/module-rma/view/frontend/email/auth.html
Customized: RMA AUTHORIZATION
Patched: vendor/magento/module-rma/view/frontend/email/new.html
Customized: New Return
Patched: vendor/magento/module-sales/view/frontend/email/creditmemo_new.html
Customized: new Credit memo - Billing
Patched: vendor/magento/module-sales/view/frontend/email/creditmemo_new_guest.html
Customized: New Credit memo Guest - Billing
Patched: vendor/magento/module-sales/view/frontend/email/invoice_new.html
Customized: New Invoice - Billing
Patched: vendor/magento/module-sales/view/frontend/email/invoice_new_guest.html
Customized: New Invoice Guest - Billing
Patched: vendor/magento/module-sales/view/frontend/email/order_new.html
Customized: New Pickup Order
Patched: vendor/magento/module-sales/view/frontend/email/order_new_guest.html
Customized: New Pickup Order For Guest
app@31fb81ebf1b1:~/html$