Remove link to Google Plus

[jpmens]

closes #1307

Overview

Google Plus no longer exists.

Testing recommendations

Link should no longer appear in

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;
• Update rebar.config.script with the correct tag once a new Fauxton release is made

[jpmens]

To whomever it may concern: the text Update rebar.config.script with the correct tag once a new Fauxton release is made in the issue template for this repo has a link to https://github.com/apache/couchdb/blob/master/rebar.config.script which is 404.

[gasp]

@jpmens tests are failing on this PR, please also fix tests by removing this line
https://github.com/apache/couchdb-fauxton/blob/main/app/addons/documentation/tests/nightwatch/checksDocsPage.js#L31

[Antonio-Maranhao]

Dup of fhttps://github.com//pull/1336. Closing