Clear cookies when switching accounts

[ClementineAccount]

This closes #8005.

This follows the suggestions proposed by Mek in internetarchive/infogami#215 (comment)
by creating handlers to call a new function that clears the cookies "pd" and "sfw"

Technical

This implementation solves the issue mentioned by clearing the cookies using a handler to infogami, overriding infogami logout function. It also does this when 'logging in' as another user from the admin panel of admin/people

Testing

(The video below under Screenshot also shows this step)

1. Login as an admin and observe the 'pd' cookie be created through the inspector
2. Logout as an admin and observe the 'pd' cookie has been cleared.
3. Login as admin again and observe that the pd cookie has been created again.
4. Login as another user using admin/people and observe that the pd cookie has been cleared.

Screenshot

I recorded this video showcasing the 'pd' cookie being cleared when the hotfix is applied. Prior to the hotfix application, the pd cookie will never be cleared.

2023-11-03.20-31-15.mp4

Stakeholders

@mekarpeles proposed the fix concept and suggested this issue to me as a 'Good First Issue' so he would likely want to review my approach prior to a merge.

[ClementineAccount]

I failed one of the CI/CD tests by accidentally importing infogami_logout twice. I have since fixed that but need to run the workflow again.

[mekarpeles]

provisional LGTM, great job -- will state on testing and give it a try

[cdrini]

Taking off testing to test #8550 .

[jimchamp]

This looks to be working as expected. Thanks, @ClementineAccount!