Find untranslated strings, add them to the locales files

[denny]

There are some bare strings in templates here and there, which should be moved into the locales file in case the CMS is translated into another language at some point.

I think the main problem areas are column headings on admin index pages and input labels on admin add/edit pages, but need to check the rest of the admin area templates too, and all of the main site templates (both the default templates and those in the included themes) - in the core code and all of the plugins.

[denny]

If you are a less experienced developer who is looking at this issue and thinking you'd like to try to take it on but you're not entirely confident, I would be happy to help you - whether that's help getting set up, more explanation of what needs doing, pairing on the code task itself, or anything else I can do to help.

In my day job I'm a lead developer who often mentors less experienced developers, and I'd love to use some of that experience to help people take their first steps into contributing to open source projects.