setup a11y info pages on all three themes

[StephDriver]

closes #4694

[StephDriver]

This includes new settings as both press and journal level. Content is just placeholder - there is another issue to write it, but I am anticipating Theme specific content (by adding theme a11y templates) with some repeated parts (Janeway, Press, Journal) which I've added as common templates.

Behaviour

• When an a11y info text field is left empty, the template doesn't display that section (rather than display a blank section).
• At press level there are two settings, one for the accessibility information, the other a boolean for whether journals can have their own information as well.
• At Journal level, if and only if the boolean above is true, then there is a setting for accessibility text in the General journal settings.
• Regardless of whether the a11y text exists at journal level, if in the future the press boolean changes, it will not display (but is not lost).

On Press

Press Manager | Edit Press Details

For Journals

Journal Manager | General
Note, this section only displays if the "allow journal accessibility information" setting at press level is enabled.

[StephDriver]

Just realised the clean theme journal footer has the accessibility link and contact link swapped around. Adding another commit to fix this and make it consistent with the order everywhere else.

[joemull]

The pages are great. I have a few suggestions about the data model and logic of the press-dependent setting mechanism.

[joemull]

I'm not so sure the settings should be invisible at the journal level. We already often have the problem that people don't understand why they can't see something that other people tell them should be there. This would re-create that problem in a new place unless someone knows that these settings are interrelated at the press and journal level. Staff might not always know how to work this feature, or communicate it to the journal editors.

What if instead of disappearing, the settings were read-only and could not be edited?

[StephDriver]

I did wonder about this for some time while working on the branch. My feeling was that in this specific instance, no or at least not yet. because I think the accessibility bit needs to be rolled out more slowly. Likely first to Press managers, so they can think about their part, and whether they want journal staff to see this or not. And only then to make it visible.

What I want to avoid is journal staff seeing the setting, and it's also the first time they've seen a setting that is not active. Particularly as by making this an 'a11y' group setting, it appears by default at the start of the all settings list.

Longer term, yes, I do think they should be visible but inactive and signposted as 'needs X setting on press'. But I don't want to introduce both inactive settings and accessibility page at the same time.

[joemull]

Just to record what we discussed off GitHub, the is_press_dependent field will need to be extended to all items in the JSON file, for consistency and maintainability.

[StephDriver]

I looked at doing this - but the file is not consistent as is - the setting attributes aren't always in the same order - so making it consistent feels like a stand alone task.