3797 improving the child functionality

[isidzukuri]

Resolves #3797

Description

Allow multiple items per child. When entering/editing a child, you should be able to choose multiple items [for example both Baby Wipes and Kids (Size 1)].

NOTE: in csv and json key item_needed_diaperid is changed to needed_item_ids.

Type of change

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• with automated test
• manually: adding/updating child with multiple needed items, viewing list of partners, exporting to csv

Screenshots

form: list view: csv:

[isidzukuri]

it requires additional testing by maintainers