Cleaning up EOL releases

[Baptiste Jonglez]

Hi Eric,

Sorry for the delay, I was traveling.

On 03-02-26, Eric wrote:
> Could the data move/reorganization be the cause of recent errors we're seeing on the
> Firmware Selector?  Maybe a redirect between 'downloads' and 'archive' or something
> like that?
> 
> Go to https://firmware-selector.openwrt.org/
> Pull down the version selector and grab, say, 22.03.7 (any older version will reproduce)
> See a CORS error:
> 
> Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at 
>     https://downloads.openwrt.org/releases/22.03.7/.overview.json.
> (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). Status code: 200.
> 
> The .overview.json file is there, well-formed and accessible, it's just that access is
> blocked by the CORS issue...

I think this is broken since we started redirecting traffic to the archive
server (in early January), because it doesn't send the CORS headers.

I've just added the needed CORS headers directly via the CDN, so that we
don't depend on whether the origin server is setting them correctly or
not.  If at some point we start directing traffic to tier-1 mirrors, we
would likely get the same issue.

Baptiste