Refactor apply options of sales rule to it's own source model to simplify extending it

[Bartlomiejsz]

Description (*)

In current Magento version, if some module needs to add it's own sales rule actions it needs to add plugin on \Magento\SalesRule\Model\Rule\Metadata\ValueProvider class and modify whole metadata class. This PR makes it easier to add/modify those actions by creating own source class for those options. Now it also becomes consistent with Catalog Rules module.

Fixed Issues (if relevant)

Manual testing scenarios (*)

1. Add after plugin on Magento\SalesRule\Model\Rule\Action\SimpleActionOptionsProvider and add new option to the array
2. It should be visible in MBO in adding new Cart Price Rule form

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)

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[magento-engcom-team]

Hi @sidolov, thank you for the review.
ENGCOM-5918 has been created to process this Pull Request

[engcom-Delta]

✔️ QA passed

[m2-assistant]

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