Add Supported Fields Based on Registrar fields bit flags

[71walceli]

This pull request includes several changes to the identity-registrar and IdentityForm components to enhance the handling of supported identity fields and improve the form's flexibility and functionality.

Enhancements to identity-registrar component:

• Added a new supportedFields property to MainContentProps to dynamically handle supported identity fields. [1] [2] [3] [4]
• Introduced a getSupportedFields function to determine supported fields based on a bitfield and updated the IdentityRegistrarComponent to use this function.

Enhancements to IdentityForm component:

• Expanded the list of identity fields with additional options such as legal, web, matrix, email, discord, twitter, image, github, and pgp_fingerprint, each with validation and transformation logic. [1] [2] [3]
• Updated the form to filter and display only the supported fields based on the supportedFields property. [1] [2]
• Improved the handling of form data and error messages to ensure proper validation and user feedback.