add checklist to sales stage

[Aryan20]

Description

Update Sales Stage to also have checklist that will create ToDo on changing the stage.

Relevant Technical Choices

Added the "Opportunity Status Checklist" field to "Sales Stage"
Moved checklist creation logic to the doc events

Testing Instructions

• Go to an opportunity
• Attempt to change stage of Opportunity
• A checklist / list from the items should be created in a ToDo

Screenshot/Screencast

Checklist

• I have carefully reviewed the code before submitting it for review.
• This code is adequately covered by unit tests to validate its functionality.
• I have conducted thorough testing to ensure it functions as intended.
• A member of the QA team has reviewed and tested this PR (To be checked by QA or code reviewer)

Fixes https://github.com/rtCamp/erp-rtcamp/issues/2468