Replace custom Metatag with either standard field or separate text fields for title & description

Overview

Per discussion in 📌 Experience builder has limited built-in metatag features, disable advanced form fields there as initial stop-gap Active the current Metatag integration on the new content type was not built in a standard way, which lead to complications.

Proposed resolution

1. Remove the custom field.
2. Either add a standard Field API Metatag field or add two separate text fields for title & description.

User interface changes

Either:
1. No change as the Metatag field is just handled differently internally.
2. The Metatag field is replaced with separate text fields for the title & description.