[OSGeoLive] OSGeoLive Docs Archive updates

[Seth G]

Hi all,

I've added the docs for v14 and v15 of OSGeoLive to the archive site at https://live-archive.osgeo.org/
I also added the dates of the releases to the index page. 

Duplicate images from versions 6.0 to 10.5 were removed as the size of the repo at https://github.com/OSGeo/OSGeoLive-doc-archive was over 10GB. This caused GitHubActions to no longer publish the site. With the duplicates removed, the repo is now half the size at under 5GB. All links in the HTML files were upated to point at the original images with a Python script. 

Seth

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