Page templates

[richard-jones]

Would be useful to have page templates so that consistency can be generated across, in particular, project pages. This could take a couple of forms:

• an html fragment which can be used to populate the text of a page on creation
• a page-specific editing form, with fields to be filled in and which will then be turned into the page source later. This would be very cool, but also significantly harder (particularly for edit)

[markmacgillivray]

duplicate see #7