Reintegrate the simple single-seller auction after unified refactor

[siddharth-sahoo]

Description

With all existing use-cases migrated to use sequential auction setups, we are left with 2 auction executor scripts in the ad-tech service's src/public/js/ssp directory -- the newer run-sequential-ad-auction.js and the older run-ad-auction.js. In addition to using sequential auction setups as the name suggests, the newer run-sequential-ad-auction.js is also capable to handling multiple ad slots and multiple ad types on the page. Increasing the flexibility from these features also increases the complexity of the script. In comparison, the existing run-ad-auction.js only executes the Protected Audience auction in a single-seller setup and can only handle a single ad slot for a display ad. This PR reintegrates the simplified single-seller Protected-Audience-only auction on the news/index page as the simplest demonstration for Protected Audience.

Affected services

• Home
• News
• Shop
• Travel
• Ad-tech
• ALL

Changelog

Changes to ad-tech

• Rename public/js/ssp/run-ad-auction.js to .../run-simple-ad-auction.js.
• Rename public/js/ssp/ssp-tag.js to .../ad-server-tag.js.
• Add HOSTNAME to JavaScript template variables.

Changes to news

• Rename the current index.ejs file to multiple-ad.ejs.
• Add a new index.ejs with a single ad unit for a fenced-frame display ad in a single-seller auction setup. Add a new view handler for the index page that is executed before the generic view handler. Specify a different AD_SERVER_TAG_URL for the index page than that used for the remaining pages. The index page uses run-simple-ad-auction.js, whereas the other pages use the more realistic ssp-tag.js which can handle multiple ad slots.
• Reformat the aside view component which lists the available demo pages on the news site.