[#672] - Added copy to the end of duplicate meal plans

[jon-dalton]

Describe the technical changes contained in this PR
duplicate_meal_plan postgres function and corresponding graphql function was changed to allow for name inputs. This was so that copy could be put at the end of duplicate meal plans and making changes to this easier for future maintainers.

Previous behaviour
Duplicate meal plans would have the exact same name as the meal plans it would copy from.

New behaviour
Duplicate meal plans have the word "copy" added to the end of their English name. This applies to duplicates of duplicates so a 3rd duplicate would be <plan> copy copy copy.

Steps to replicate
Log in to meal-planner ui
Create a meal
Click the copy/duplicate button on a meal plan card
Click the copy/duplicate button on the duplicate's meal plan card to observe duplicate of duplicates behaviour.

Related issues addressed by this PR
Fixes #672

Have the following been addressed?

• Have test cases been created for all of the changes?
• Do all of the test cases pass?
• Has the testing been done using the default docker-compose environment?
• Are documentation changes required?
• Does this change break or alter existing behaviour?