Add documentation on open access publishing

[cassgvp]

We are removing some of the content from the main Open WIN pages and redirecting WIN members and interested external parties to the Open WIN Community pages. Note that the intention for the community pages is to mainly be of internal relevance, but to be developed openly and available for external review.

The community pages have no information on open access publishing. This is of particular relevance for internal communications to WIN members, not least because of the the recent changes in requirements for open access publishing introduced by Wellcome. There is a section one the WIN pages about "Publishing Openly", but this does not contain the guidance which might be expected from the title (specifically information about open access publishing).

The feature request suggests we include a new page(s) in this repo detailing the benefits of open access publishing, along with any background information which might be necessary for context. This page(s) should also outline the requirements for open access mandated by Wellcome and direct readers to other University of Oxford resources where appropriate, for example these courses offered by the Bodliean.

[cassgvp]

Added a page holder and basic information from the text of the WIN Newsletter of October 2020. See commit a3dadc4.