[Backport] [Fix #16655] Block totalbar not used in invoice create and credit memo create screens

[dverkade]

Original PR

• [Fix #16655] Block totalbar not used in invoice create and credit memo create screens #16656

Description

Upon investigation there is a totalbar block in the create invoice and credit memo screens which is not being used. This PR addresses that:

• Removed the unused Totalbar block from the invoice create and credit memo create layouts.
• Deprecated Totalbar class
• Deprecated totalbar template file

Fixed Issues

1. Block totalbar not used in invoice create and credit memo create screens #16655: Block totalbar not used in invoice create and credit memo create screens
2. Not possible to create an invoice in Magento 2.3 #16653: Not possible to create an invoice in Magento 2.3

Related PR's

There is a PR related to this PR, which does not solve the issue correctly.

1. $block->getTotals() is not countable #16563: $block->getTotals() is not countable

Manual testing scenarios

1. Create a new order
2. Create an invoice, screen will look the same as before the changes.
3. Update invoice quantity, screen will look the same as before the changes.
4. Create a credit memo, screen will look the same as before the changes.
5. Update credit memo quantity, screen will look the same as before the changes.

[sidolov]

Hi @dverkade , due to changes in Magento Code Contributions Guide we can't accept such Pull Requests to 2.1 release line. All code cleanup like typos, spelling mistakes, removing unused code, etc should be delivered to 2.3 release line.
Thank you!

[dverkade]

@sidolov I think this is more a bugfix then code cleanup, see related issue: #16655

[sidolov]

Hi @dverkade , I agree with you, sorry for the mistake.
Reopen this PR due to bugfix.
Thank you!

[magento-engcom-team]

Hi @sidolov, thank you for the review.
ENGCOM-2691 has been created to process this Pull Request

[magento-engcom-team]

Hi @dverkade. Thank you for your contribution.
We will aim to release these changes as part of 2.1.16.
Please check the release notes for final confirmation.