Issue #3512: Create special form widget for vCard email field

[stefan-korn]

possible fix to #3512

This only addresses the issue with editing the email field through the UI for a vCard with the hasEmail property that was imported via the API.

Steps to Recreate

• Create a dataset through the API / via a harvest that has a contactPoint with the hasEmail property

"contactPoint": { "@type": "vcard:Contact", "fn": "First Name", "hasEmail": "mailto:email@example.com" },

• Attempt to edit the dataset through the UI. The validation of the email field fails.

QA Steps

• Create a dataset through the API / via a harvest that has a contactPoint with the hasEmail property
• Only the email appears in the email form field (no mailto:)
• Edit and save the dataset through the UI without an error.
• When visiting the API path for the metastore ( /api/1/metastore/schemas/dataset/items/{identifier} ) the hasEmail still shows the mailto: prefix.

[jastraat]

Followed the QA steps as outlined, and this allowed editing a previously created via the API dataset with an email containing a hasEmail property through the UI and saving successfully.