[Xon] Proxy Link-Forum 2.4.1

• Fix "LogicException: Must provide at least 1 metadata value" when a crafted search url using a non-existent forum

• Reduce number of joins when fetching proxied forum data
• Make proxy link forums excluded from XF permission building, and push view check to proxied forum/category.
  This eliminates the overhead on permission rebuilding on adding proxy link forums to the node-tree.
• Known issue of disabling a proxy link forum from proxying doesn't cause permissions to be rebuild for the node.

• Remove unused template modification
• Fix proxied forums/categories did not display stats from the sub-forums of the proxied forum/category

• Require php 7.2
• XenForo 2.2+
• Add per-link-forum "Include proxied forum in search results" option (default true)
• Fix "Search sub-forums as well" did not include proxied forums/categories

• Fix template error on node list page when marking a link proxy forum as a proxy

• Fully remove XF2.0 support
• Proxied node stats are now correctly propagated
• Add category support, thanks @Lukas W.

Compatibility fix for ElasticSearch Essentials auto-complete when Gift Upgrades is also installed

XenForo 2.2.4 compatibility update

Compatibility fix for ElasticSearch Essentials auto-complete when Gift Upgrades is also installed

Fix destination forum view checks where not always performed before displaying information from that forum
Fix destination forums would not always be considered for quick search or via the "Search sub-forums as well" feature
Inject if a link forum is a proxy in the node list & node permission list