Set custom namespaces for compatibility files

[sybrew]

Currently, the compatibility files use the plugin's global namespace The_SEO_Framework.

This can cause issues if two or more plugins of the same type are introduced, where we didn't think too long about the names for the functions.

Also, prefixing all function names with, e.g., _wpforo for WP Foro, is making things difficult to read and manage.