feat(ta-730): add partitioned cookie config

[mike-dean-talis]

Problem

• TA-730

On analysing Elevate's use of LTI.js, we identified that it requires third party cookies. The library has not yet been updated to change this particular feature.

In order for LTI launches to continue to work in Elevate (at least for Chrome-based browsers), we require a solution that allows these cookies to be processed in a PKCE workflow.

The current solution to this issue is partioned cookies.

Elevate cannot support this at an LTI.js level, nor at the Express.js level so we must resort to a supporting configuration in nginx.

This new property will load a supporting nginx configuration.

[mike-dean-talis]

comment: I am looking for some critique and advice for this PR.

I am not sure if I am:

• Configuring nginx to do what we're after (hopefully that's clear from the PR description)
• A good guide to actually testing this

[mrliptontea]

Could you include a test with multiple locations? I want to ensure each entry location directive starts on its own line.