Refactor Subscriber Modal Page

[yccodr]

Description

This PR is mainly focusing on refactoring the subscriber create/update page. It aims to reduce the complexity of the page and separate it into multiple components. Also, this PR adds react-hook-form to help with validation and improving performance.

Changes

• New Mapper Layer
  • map subscription model to form schema (called SubscriptionDTO in codebase)
  • hide complex logic from presentation layer (form, in this case)
• Form state management: useState() -> useForm()
• Added some validation:
  • userNumber should be a positive integer
  • plmnId should be a five digit number string
  • etc
• Modular components: split 1700-ish-line page into multiple 200-ish-line components
• New Dependencies: react-hook-form, @hookform/resolvers, zod
• Allow empty SD value (closes Webconsole shall not require SD when provisioning a 5G subscriber #19 )

[yccodr]

@ianchen0119 @andy89923 Ready for review! 🙏