Alter approach to social profile retrieval on profile templates

[jonoaldersonwp]

The sidebar on profile templates contains a 'Find me on' section, which includes social profile links sourced from the users' Gravatar profile. These icons are fetched and output via a JavaScript function / ajax process.

Other (pending) enhancements require that we have access to this data earlier in the page, and, server-side. This necessitates a shift to a server-side process for fetching these icons.

Specifically:

• The JavaScript function(s) used to retrieve the Gravatar social profiles should be removed.
• A new server-side process should be introduced, using either ​https://en.gravatar.com/site/implement/profiles/php/ or ​https://en.gravatar.com/site/implement/profiles/json/.
• Values should be cached for an appropriate period of time, and ideally, flushed on profile update.

[coffee2code]

Also see #4280, which is partially dependent on this ticket.

[coffee2code]

For some quick background, in the original implementation of the current Profiles design, the Gravatar profile information was requested directly on the server ([dotorg-8439], [dotorg-8440]) rather than fetched client-side as is currently the case (changed in [dotorg-8807]).

The original implementation resulted in replication lag.

[jonoaldersonwp]

This causes front-end performance issues (layout shift), as well as being explicitly bad for SEO and accessibility.

[jonoaldersonwp]

Closing, as this is no longer present in the template.