Order Client Plugin Update

[dalyathan]

Description

• registerCustomerAccount, requestPasswordReset and resetPassword checkout operations have been implemented.
• Added contribution/development guide about generating types
• Added $currentUser store
• Always return ActiveOrder<A> or ActiveOrder<A> | undefined for consistency. Don't use ActiveOrderFieldsFragment

Breaking changes

• Not exporting all generated types anymore
• Don't return undefined for most mutations
• Removed getters/setters: Consumers should use useStore(client.$activeOrder)

Checklist

📌 Always:

• I have set a clear title
• My PR is small and contains only a single feature. (Split into multiple PR's if needed)
• I have reviewed my own PR, fixed all typo's and removed unused/commented code

⚡ Most of the time:

• I have added or updated test cases for important functionality
• I have updated the README if needed

📦 For publishable packages:

• Have you correctly increased the version number in package.json to the next patch/minor/major?
• Have you added your changes to the changelog?

[martijnvdbrug]

Made some cahnges, but other than that: great!