Add link to article types to Details page and track clicks

[hdrury1]

We have a small number of submissions that are hitting eJP with the wrong article type and which then need to be changed by staff. The assumptions we are trying to prove with this experiment are that:

1. Users have difficulty in selecting the appropriate article type for their submission
2. Users will read readily available information and make more informed decisions as a result

We anticipate seeing a decrease in the number of incorrect article types.

We should:

[ ] Add line of text to details step as per wireframe (note styling is not quite Paragraph.Reading)
[ ] Link to article types paragraph in author guide (anchor at 'Research Articles' on this page https://staging--xpub.elifesciences.org/author-guide/types). The link should open in a new tab.
[ ] Embed Google Analytics code to track click event

https://projects.invisionapp.com/share/P3T4TU7U8ZQ#/screens/375554399