Make sure users can override template elements if they need to

[timpaul]

For example:

• open graph image
• crown copyright
• OGL
• skiplink location
• page language
• custom attributes on body tag

This issue has come up a number of times:

• Allow overriding / removal of OGL logo govuk_template#188
• Open graph image govuk_template#137
• Skip link is hardcoded to point at #content govuk_template#271
• HTML title Language set incorrectly [i18n] [a11y] govuk_template#342
• Add block variable for body attributes govuk_template#285
• Open graph image path needs to be customisable #813

[hannalaakso]

Split this into cards (apart from the skiplink location one as that functionality already exists):

https://trello.com/c/GbXpmjYJ/1420-add-ability-to-override-or-remove-open-graph-meta-tag-in-template
https://trello.com/c/ZB1o8lcI/1421-add-ability-to-override-or-remove-crown-copyright-in-footer
https://trello.com/c/8VjEokHR/1426-add-ability-to-override-or-remove-ogl-logo-in-footer
https://trello.com/c/Be65Mgph/1429-add-ability-to-override-language-for-page-title-and-main-in-template
https://trello.com/c/nVhT0Foq/1431-add-ability-to-set-attributes-on-body-in-template

Closing this card as there doesn't seem to be any value in tracking these changes as a single item.

[edwardhorsford]

This just came up on my service. We'd been using the footer without thought to the OGL text. I'm so used to seeing it I didn't think about whether it was correct to use.

Some services contain official / confidential information and it would be inappropriate to release under the OGL.

[aliuk2012]

Closing this issue as these have been split out into separate tickets