US, AU news link change.
Respect the `sessionCookie` flag for the SC_GU_LA cookie [#MEM-403]

This is part of the work to enforce that users are recently signed-in
when they view their personal profile:

https://profile.theguardian.com/account/edit

The Identity API will now be proving Cookie info for the new SC_GU_LA
cookie, which stores when the user last authenticated:

https://github.com/guardian/identity/pull/176

...this change to NGW Frontend is required to get it to respect the new
`sessionCookie` flag, so that the SC_GU_LA cookie is only session-scoped
and dies when the user closes the browser.

https://jira.gutools.co.uk/browse/MEM-403
New containers.
Fronts on-page description
Sublink hover behaviour
remove placeholder of on-page description field
Start removing blockVideoAds metadata property
remove "twitter:image:src" meta tag
Merge pull request #6193 from guardian/support-session-scoped-identity-cookies

Respect the `sessionCookie` flag for the SC_GU_LA cookie [#MEM-403]
Fix flakey Slice with Cards test
Merge pull request #6213 from guardian/fix-flakey-test

Fix flakey Slice with Cards test
Revert "Respect the `sessionCookie` flag for the SC_GU_LA cookie [#MEM-403]"
Merge pull request #6214 from guardian/revert-6193-support-session-scoped-identity-cookies

Revert "Respect the `sessionCookie` flag for the SC_GU_LA cookie [#MEM-4...
Change video JavaScript to use a data attribute for ad blocking
Article and sublink open/close behaviour
Merge remote-tracking branch 'origin/master' into remove-meta-tag
remove "twitter:image:src" meta tag from tests
Merge pull request #6211 from guardian/remove-tooltip

Remove placeholder of on-page description field in facia-tool
Correct order of article buttons
Merge pull request #6215 from guardian/facia-tool-sublinks

facia tool: better sublink behaviour