Add ProfilePage to schema metatag module

@daveb Two questions?

1) Does interest in this as a paid project mean that you are looking to pay someone to implement this feature or you are looking for someone to pay you to implement this feature? Either is fine, but it's not clear to me what you are asking for yet.

2) I was going to ask if this is necessary, given the current ability for Backdrop to link content authors to users profiles on the site. BUT, as I looked closer at the link you provided and I see that there may be value in adding this data to the metatags for search engines such as Google. 

"ProfilePage markup is designed for any site where creators (either people or organizations) share first-hand perspectives. It helps Google Search highlight information about the creator, such as their name or social handle, profile photo, follower count, or the popularity of their content. Google Search also makes use of this markup when disambiguating the creator, and in features such as ..."

Hi @daveb. I would be happy to give you a price for this. In the absence of any private messaging function, you can contact me through my website or LinkedIn.

If you visit my Backdropcms.org profile at https://backdropcms.org/account/yorkshirepudding you can see the modules I'm involved in (either created for Backdrop, ported to Backdrop, or taken on the maintainer role and added features/fixed bugs). You can also see a link to my website and LinkedIn profile. You can also see a link to my GitHub profile which will show all the contributions I make across Backdrop.