Annotate Protips with structured data

Work on https://assembly.com/coderwall/bounties/384.

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@seuros it was defined by some one else in the https://github.com/assemblymade/coderwall/blob/master/app/helpers/application_helper.rb#L240

I asked in my previous comment whether I should rename those also as part of this PR. What do you think?
Because that file already had `mperson` and `maddress` I added methods `mtecharticle` and `mcomment`.