Enforce Connected Social Pages link format

[sybrew]

Google Business Profile says its users should respect specific formats for URLS: https://support.google.com/business/answer/13580646.

These are:

• Facebook - https://www.facebook.com/{username}
• Instagram - https://www.instagram.com/{username}
• LinkedIn - https://www.linkedin.com/in/{username}
• Pinterest - https://www.pinterest.com/{username}
• TikTok - https://www.tiktok.com/{username}
• Twitter - https://www.twitter.com/{username}
• YouTube - https://www.youtube.com/channel/{username}
• YouTube - https://www.youtube.com/user/{username}
• YouTube - https://www.youtube.com/@{username}

We may also want to enforce this format for our users, or at least suggest it to them.

[sybrew]

We provide inputs for Soundcloud and Tumblr, which aren't in the list above.
We do not provide an input for TikTok, which we should.