Partial import of Extensions

By default only the extension file is proxied from external source. Since XWiki 9.5RC1 you can bump proxy level up and proxy also previous extension versions and their dependency information. After update of extensions this information will no longer be kept in document objects but, when requested, proxied from external source. This may be enabled by setting Proxy Level attribute of ExtensionProxy XObject to File and Previous Versions. The point of bumping up proxying level is to save space in XWiki database.